Science Knowledge - 2 - Year 5 MCQ

The Audible Range of Sound
The audible range of sound refers to the range of frequencies that can be heard by the human ear. It is the range of frequencies that are perceived as sound and can be detected by the sensory organs in our ears.
The correct answer is B: 20 Hz to 20 kHz.
Explanation:
- The audible range of sound can be broken down into three main categories: low frequencies, mid frequencies, and high frequencies.
- Low frequencies are typically below 20 Hz and are often felt more than heard. Examples of low-frequency sounds include earthquakes or thunder.
- Mid frequencies range from 20 Hz to 2 kHz and are the most commonly heard sounds in our everyday lives. This includes the sounds of speech, music, and most environmental sounds.
- High frequencies range from 2 kHz to 20 kHz and are often associated with sounds like bird chirping or the high notes of a musical instrument.
- Above the audible range, there are ultrasonic frequencies (above 20 kHz) that are not detectable by the human ear.
- Similarly, below the audible range, there are infrasonic frequencies (below 20 Hz) that are also not perceived as sound by humans.
In conclusion, the audible range of sound for humans is from 20 Hz to 20 kHz, with frequencies below and above this range being either too low or too high to be heard.

The nephron is:
The functional unit of the kidney.
Explanation:
The nephron is a small structure within the kidney that is responsible for filtering and processing blood to produce urine. It is considered the functional unit of the kidney because it performs all the essential tasks required for urine formation.
Key Points:
1. Structure: The nephron consists of several components, including the glomerulus, proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct.
2. Filtration: The glomerulus, a network of tiny blood vessels, filters waste products, toxins, and excess water from the blood.
3. Reabsorption: The proximal convoluted tubule reabsorbs important substances such as glucose, amino acids, and electrolytes back into the bloodstream to maintain their balance.
4. Concentration: The loop of Henle plays a crucial role in concentrating urine by creating a concentration gradient within the kidney.
5. Regulation: The distal convoluted tubule adjusts the final composition of urine by selectively reabsorbing or secreting certain ions and substances.
6. Collection: The collecting duct collects the urine from multiple nephrons and transports it towards the renal pelvis for storage before it is excreted from the body.
Conclusion:
The nephron is the functional unit of the kidney responsible for filtering and processing blood to produce urine. Its various components work together to maintain the body's fluid and electrolyte balance.

Salt used in photography: Silver Nitrate
Silver nitrate is the salt that is commonly used in photography. It plays a crucial role in the development of photographic film and the production of black and white prints. Here is a detailed explanation:
1. Introduction:
- Salt is an essential component in the field of photography.
- Different types of salts are used for various purposes in the photographic process.
2. Importance of salt in photography:
- Salt is used to sensitize film and photographic paper to light.
- It helps in capturing and developing the image.
3. Types of salts:
- Various salts are used in different stages of the photographic process.
- Some common salts include:
a. Silver nitrate
b. Sodium nitrate
c. Sodium chloride (common table salt)
4. Purpose of silver nitrate:
- Silver nitrate (AgNO3) is a highly light-sensitive salt.
- It is primarily used in the preparation of photographic emulsions.
- Silver nitrate reacts with light to produce silver ions, which form the latent image on photographic film.
5. Other uses of silver nitrate:
- Apart from photography, silver nitrate has various other applications.
- It is used in medicine, chemistry, and silver-based products.
6. Conclusion:
- Silver nitrate is the salt used in photography for its light-sensitive properties.
- It plays a vital role in the development of photographic film and the production of black and white prints.

Elephants have a pair of elongated, curved teeth known as tusks. These tusks are specialized incisors that grow continuously throughout an elephant's life. The tusks are actually modified versions of the incisors in the upper jaw.
Here is a detailed explanation of why the answer is C: Incisors of the upper jaw.
The tusks of elephants:
- The tusks of elephants are large, long, and protruding structures that serve various purposes.
- They are composed of ivory, a dense and durable material.
- Tusks can grow up to several meters in length and can weigh hundreds of kilograms.
- Both male and female elephants can have tusks, although they are generally larger in males.
The function of tusks:
- Tusks are primarily used for various tasks, including digging, foraging, and lifting objects.
- They are also important for defense and fighting, as elephants use their tusks to ward off predators or engage in dominance battles.
- Tusks can also be used as a symbol of social status and attractiveness during mating rituals.
The origin of tusks:
- Tusks are derived from the incisors, which are the front teeth in the upper jaw of elephants.
- These incisors are initially small and continue to grow throughout the elephant's life.
- As they grow, they form the long, curved tusks that we commonly associate with elephants.
- The tusks are essentially enlarged and modified versions of the upper incisors.
Therefore, the correct answer is C: Incisors of the upper jaw.

Tip of the match-stick contains red phosphorus.


Explanation:


The tip of a matchstick contains red phosphorus, which is a chemical compound used for its ignition properties. Here is a detailed explanation of why red phosphorus is present in the matchstick tip:
- Ignition process: When the matchstick is struck against the matchbox, the friction between the match head and the rough surface of the matchbox creates heat and ignites the match.
- Composition of matchstick tip: The tip of the matchstick consists of a mixture of red phosphorus, powdered glass, and an oxidizing agent, such as potassium chlorate. This composition is known as the match head or ignition compound.
- Red phosphorus: Red phosphorus is a less reactive and more stable form of phosphorus compared to white phosphorus. It is obtained by heating white phosphorus in the presence of a reducing agent. Red phosphorus does not ignite spontaneously in air and is therefore safer to handle.
- Role of red phosphorus: Red phosphorus acts as a catalyst during the ignition process. When the matchstick is struck, the friction generates enough heat to convert a small amount of red phosphorus into white phosphorus vapor. The white phosphorus vapor then reacts with the oxidizing agent, releasing energy in the form of heat and light, which ignites the matchstick.
- Other components: The powdered glass in the match head helps in the initial ignition by providing a rough surface for the friction. The oxidizing agent, such as potassium chlorate, provides the necessary oxygen for the combustion reaction.
In conclusion, the tip of a matchstick contains red phosphorus, which plays a crucial role in the ignition process by acting as a catalyst. The presence of red phosphorus, along with other components, allows the matchstick to ignite when struck against a rough surface.

Commercial Name of Sodium Bicarbonate
Baking Soda
Sodium bicarbonate is commonly known by its commercial name, which is baking soda. It is a white crystalline powder that is commonly used in baking, cooking, and as a household cleaning agent.
Explanation:
Definition: Sodium bicarbonate is a chemical compound with the formula NaHCO3. It is a salt composed of sodium ions (Na+) and bicarbonate ions (HCO3-).
Commercial Name: Sodium bicarbonate is widely recognized and sold under the commercial name baking soda.
Usage: Baking soda has various applications in different fields, including:
- Baking: Baking soda is a leavening agent commonly used in baking to make dough rise. It reacts with acids in the recipe, releasing carbon dioxide gas, which causes the dough to expand and become light and fluffy.
- Cooking: Baking soda is also used in cooking as a tenderizer for meats and in certain recipes to neutralize acidic flavors.
- Cleaning: Baking soda is a versatile cleaning agent and is often used as a natural alternative to harsh chemical cleaners. It can be used to remove stains, deodorize surfaces, and unclog drains.
- Personal Care: Baking soda is a common ingredient in toothpaste, deodorants, and bath products due to its mild abrasive and odor-neutralizing properties.
Conclusion:
The commercial name of sodium bicarbonate is baking soda. It is a versatile compound used in baking, cooking, cleaning, and personal care products for its various properties and applications.

The Pituitary Gland Produces Growth Hormone
The pituitary gland, also known as the "master gland," is responsible for producing and releasing various hormones that regulate numerous bodily functions. One of the hormones produced by the pituitary gland is growth hormone (GH), also known as somatotropin. GH plays a crucial role in stimulating growth and development in the human body.
Functions of Growth Hormone:
- Stimulates growth and development of bones and tissues
- Promotes protein synthesis and cell division
- Enhances muscle growth and strength
- Regulates metabolism and fat utilization
Effects of Growth Hormone Deficiency:
- Stunted growth in children
- Decreased muscle mass and strength
- Increased body fat
- Reduced bone density
Importance of Pituitary Gland:
- The pituitary gland is located at the base of the brain and is responsible for controlling the function of other endocrine glands in the body.
- It secretes various hormones that regulate growth, reproduction, metabolism, and other vital processes.
- The pituitary gland is divided into two main parts: the anterior and posterior pituitary. The anterior pituitary produces and releases growth hormone.
In summary, the pituitary gland, located in the brain, is responsible for producing growth hormone (GH). GH plays a crucial role in stimulating growth and development in the body.

From an evolutionary point of view, the dolphin (option B) is considered to be more advanced compared to the other options:
1. Adaptation to Aquatic Environment:
- Dolphins are fully aquatic mammals and have adapted to life in water, which is considered a more advanced evolutionary trait.
- Crocodiles, sharks, and tortoises are all primarily associated with their respective environments, but dolphins have evolved to thrive exclusively in water.
2. Brain Complexity:
- Dolphins have larger and more complex brains compared to crocodiles, sharks, and tortoises.
- The advanced cognitive abilities of dolphins, such as problem-solving, communication, and social behavior, are indicative of their higher level of evolutionary development.
3. Social Behavior and Communication:
- Dolphins exhibit highly complex social structures and communication systems.
- They live in social groups, display cooperative hunting techniques, and have a wide range of vocalizations.
- Crocodiles, sharks, and tortoises do not exhibit such intricate social behaviors or communication methods.
4. Echolocation Abilities:
- Dolphins possess the ability to use echolocation, which allows them to navigate and locate prey using sound waves.
- This sophisticated sensory skill is absent in crocodiles, sharks, and tortoises.
5. Mammalian Characteristics:
- Dolphins are mammals and share several advanced traits with other mammals, such as live birth, nursing their young, and having a warm-blooded metabolism.
- Crocodiles and sharks are reptiles, while tortoises are reptiles with primitive characteristics.
Overall, the dolphin's adaptation to aquatic life, complex brain, social behavior, communication skills, echolocation abilities, and mammalian characteristics make it more advanced from an evolutionary perspective compared to crocodiles, sharks, and tortoises.

Mineral required for muscle contraction:
Answer: A. Calcium
Explanation:
Muscle contraction is a complex process that requires the involvement of various minerals and ions. Among these, calcium plays a crucial role in initiating and regulating muscle contractions. Here's a detailed explanation:
1. Importance of Calcium:
- Calcium is an essential mineral for many bodily functions, including muscle contraction.
- It is required for the interaction between actin and myosin, the proteins responsible for muscle contraction.
- Calcium ions bind to troponin, a regulatory protein, allowing actin and myosin to form cross-bridges and initiate muscle contraction.
2. Muscle Contraction Process:
- When a muscle receives a signal from the nervous system, it undergoes a series of events to contract.
- The signal triggers the release of calcium ions from the sarcoplasmic reticulum, a specialized structure within muscle cells.
- The released calcium ions bind to troponin, causing a conformational change in the troponin-tropomyosin complex.
- This conformational change exposes the binding sites on actin, allowing myosin heads to attach and form cross-bridges.
- The interaction between actin and myosin leads to the sliding of muscle filaments, resulting in muscle contraction.
3. Other Minerals:
- While calcium is the primary mineral involved in muscle contraction, other minerals also play important roles.
- Sodium and potassium ions are involved in generating the electrical impulses that initiate muscle contractions.
- Iron is essential for oxygen transport and energy production in muscles, but it does not directly participate in the contraction process.
- Zinc is involved in various enzymatic reactions and overall muscle health but is not directly involved in muscle contraction.
In conclusion, calcium is the mineral required for muscle contraction. It is involved in the regulation and initiation of muscle contractions by allowing actin and myosin to interact.

The main component of vinegar is acetic acid, which gives a sour taste and pungent aroma. The acetic acid content of the different vinegars present in the global market usually ranges from four to seven acetic degrees (w/v; 4–7 g acetic acid/100 ml of vinegar).

The Pituitary Gland
- The pituitary gland, also known as the "master gland," is a small pea-sized gland located at the base of the brain.
- It is connected to the hypothalamus by a stalk called the pituitary stalk or infundibulum.
- The hypothalamus is responsible for regulating various bodily functions and produces hormones that control the release of hormones from the pituitary gland.
- The pituitary gland receives messages from the hypothalamus through the release of hormones into the bloodstream.
- The hormones released by the hypothalamus stimulate or inhibit the release of hormones from the pituitary gland.
- The pituitary gland then communicates with other endocrine glands in the body through the release of its own hormones.
Functions of the Pituitary Gland
- The pituitary gland is responsible for regulating and controlling the functions of several other endocrine glands in the body.
- It secretes various hormones that target specific glands and organs.
- Some of the hormones released by the pituitary gland include:
- Growth hormone (GH): stimulates growth and development in children and regulates metabolism in adults.
- Thyroid-stimulating hormone (TSH): controls the production and release of thyroid hormones from the thyroid gland.
- Adrenocorticotropic hormone (ACTH): stimulates the release of cortisol from the adrenal glands.
- Follicle-stimulating hormone (FSH) and luteinizing hormone (LH): regulate reproductive functions and the production of sex hormones.
- The pituitary gland acts as a central control system, receiving messages from the hypothalamus and coordinating the release of hormones to maintain hormonal balance in the body.
In conclusion, the pituitary gland receives messages from the hypothalamus and communicates with other endocrine glands in the body. It plays a crucial role in regulating various bodily functions by releasing hormones that target specific glands and organs.

The part of grain in cereals, where much of the protein lies is the Aleurone layer.
The aleurone layer is an important component of cereal grains, such as wheat, rice, and barley. It is located between the endosperm and the bran layers. Here is a detailed explanation of why the aleurone layer is the part of the grain where much of the protein lies:
1. Aleurone Layer:
- The aleurone layer is a thin outer layer of cells in the endosperm of cereal grains.
- It is highly protein-rich and contains enzymes that are important for the germination of the grain.
- The proteins in the aleurone layer are mainly storage proteins, such as globulins and albumins.
2. Protein Content:
- The aleurone layer accounts for a significant portion of the total protein content in cereal grains.
- The protein content in the aleurone layer can range from 5% to 15% or more, depending on the grain type.
- This protein is a valuable source of essential amino acids and is important for human nutrition.
3. Nutritional Importance:
- The protein in the aleurone layer plays a crucial role in providing essential amino acids for growth and development.
- It is a good source of lysine, an amino acid that is often limited in other cereal proteins.
- The aleurone layer also contains other important nutrients, such as vitamins, minerals, and dietary fiber.
4. Processing:
- During the milling process, the aleurone layer is often removed along with the bran layer to produce white flour.
- This can result in a significant loss of protein and other nutrients.
- However, whole grain products, such as whole wheat flour and brown rice, retain the aleurone layer and thus have a higher protein content.
5. Health Benefits:
- Including whole grain products in the diet can provide the benefits of the protein-rich aleurone layer.
- Whole grains have been associated with a reduced risk of chronic diseases, including heart disease, type 2 diabetes, and certain types of cancer.
- The protein and other nutrients in the aleurone layer contribute to these health benefits.
In conclusion, the aleurone layer is the part of the grain in cereals where much of the protein lies. It is a protein-rich layer located between the endosperm and the bran layers. The protein in the aleurone layer is important for human nutrition, providing essential amino acids and other nutrients. Including whole grain products in the diet can help reap the health benefits associated with the aleurone layer's protein content.

The Smallest Bone in the Human Body
The smallest bone in the human body is called the stapes, and it is found in the ear. Here is a detailed explanation of this interesting fact:
Anatomy of the Ear
- The human ear is divided into three main parts: the outer ear, the middle ear, and the inner ear.
- The outer ear consists of the pinna, or the visible part of the ear, and the ear canal.
- The middle ear is a small, air-filled space located behind the eardrum.
- The inner ear is a complex structure that contains the cochlea, responsible for hearing, and the vestibular system, responsible for balance.
The Stapes
- The stapes, also known as the stirrup bone, is one of the three small bones in the middle ear called the ossicles.
- The ossicles connect the eardrum to the inner ear and play a crucial role in transmitting sound vibrations.
- The stapes is the smallest and lightest bone in the human body, measuring only about 2.8 millimeters in length.
- Its shape resembles a stirrup, hence the name "stapes."
Function of the Stapes
- When sound waves enter the ear, they cause the eardrum to vibrate.
- These vibrations are then transferred to the ossicles, starting with the malleus (hammer bone), followed by the incus (anvil bone), and finally reaching the stapes.
- The stapes transmits the vibrations to the fluid-filled cochlea in the inner ear.
- The cochlea converts these vibrations into electrical signals that are sent to the brain, allowing us to perceive sound.
Conclusion
- The stapes, located in the middle ear, is the smallest bone in the human body.
- Its tiny size and crucial role in transmitting sound vibrations highlight the intricate and fascinating nature of the human ear.

System Attacked by HIV: Immune System
- HIV (Human Immunodeficiency Virus) primarily attacks the immune system of the body.
- The immune system is responsible for defending the body against infections and diseases.
- HIV specifically targets and attacks CD4 T cells, which are a type of white blood cell involved in immune responses.
- The virus enters the CD4 T cells, replicates inside them, and destroys them, leading to a weakened immune system.
- As HIV progresses, the number of CD4 T cells decreases, making the body more susceptible to opportunistic infections and certain types of cancers.
- The weakened immune system results in a condition called AIDS (Acquired Immunodeficiency Syndrome), which is the advanced stage of HIV infection.
- AIDS is characterized by severe immune system damage and a high risk of developing life-threatening infections and diseases.
Therefore, the correct answer is B: Immune System. HIV primarily attacks and weakens the immune system of the body.

Stem Tissue:
- The stem tissue is a part of the plant that provides support and transportation of water, nutrients, and sugars between the roots and leaves.
- It also helps in the growth and development of the plant.
Options:
A: Carrot
- Carrot is a taproot vegetable.
- The edible part of the carrot is the root, not the stem tissue.
B: Cactus
- Cactus is a succulent plant.
- The stem tissue of the cactus is fleshy and stores water.
- It helps the cactus survive in arid environments.
- Therefore, cactus has stem tissue.
C: Ginger
- Ginger is a rhizome.
- The part that we use for culinary purposes is the underground stem tissue.
- It stores food and nutrients for the plant.
D: Flower
- The flower is a reproductive structure of the plant.
- It does not have stem tissue.
Conclusion:
Among the given options, only option B (Cactus) has stem tissue. Cactus has fleshy stem tissue that stores water and helps the plant survive in arid environments.

Vaccines: Detailed Solution
Vaccines are biological substances that help prevent infectious diseases by stimulating the immune system to recognize and fight against specific pathogens. Here is a detailed explanation of vaccines:
Definition: Vaccines are substances that contain weakened or inactivated forms of bacteria or viruses or their proteins. They are designed to stimulate an immune response in the body, without causing the actual disease.
Function: Vaccines train the immune system to recognize and respond effectively to specific pathogens. They can prevent diseases by either:
- Active Immunization: This involves introducing the body to a harmless form of the pathogen, triggering an immune response and the production of memory cells. If the person is later exposed to the actual pathogen, their immune system can quickly recognize and neutralize it, preventing the disease from developing.
- Passive Immunization: Some vaccines contain antibodies that are already produced by other individuals or laboratory techniques. These antibodies provide immediate protection against specific diseases, but the immunity is temporary and does not provide long-term protection like active immunization.
Components: Vaccines can contain various components, including:
- Weakened or Inactivated Pathogens: These are used in live attenuated vaccines or inactivated vaccines, respectively.
- Proteins: Vaccines may contain specific proteins from the pathogen, such as surface proteins or toxins, to stimulate an immune response.
- Adjuvants: These are substances added to vaccines to enhance the immune response and increase the effectiveness of the vaccine.
- Preservatives and Stabilizers: Vaccines may contain small amounts of preservatives and stabilizers to maintain their potency and prevent contamination.
Types: There are different types of vaccines, including:
- Live Attenuated Vaccines: These contain weakened forms of the live virus or bacteria, which can still replicate but cause only mild or no symptoms. Examples include the measles, mumps, and rubella (MMR) vaccine.
- Inactivated Vaccines: These contain killed or inactivated viruses or bacteria. The polio vaccine is an example of an inactivated vaccine.
- Subunit, Recombinant, and Conjugate Vaccines: These contain specific proteins or protein fragments from the pathogen. Examples include the hepatitis B vaccine and the human papillomavirus (HPV) vaccine.
- Toxoid Vaccines: These contain inactivated toxins produced by the pathogen. The tetanus vaccine is an example of a toxoid vaccine.
Importance: Vaccines have played a crucial role in preventing the spread of infectious diseases and reducing their impact on public health. They have helped eradicate diseases like smallpox and significantly reduce the incidence of diseases like polio, measles, and rubella.
In conclusion, vaccines are not the same as monoclonal antibodies (A). They are composed of treated bacteria or viruses or their proteins (B), which stimulate the immune system to provide protection against specific pathogens. MHC proteins (C) are molecules involved in presenting antigens to immune cells, not the main components of vaccines. Strands of nucleic acid (D) are used in some newer vaccine technologies like mRNA vaccines, but not

Antibacterial Dye for Skin Infection: Gentian Violet
Gentian violet is a commonly used antibacterial dye for the treatment of skin infections. It has been used for many years due to its effectiveness against a wide range of bacteria and fungi. Here are some key points about gentian violet:
1. Properties:
- Gentian violet is a synthetic dye that is derived from coal tar.
- It is a dark purple color and has strong antibacterial and antifungal properties.
- It is commonly used as a topical treatment for various skin infections.
2. Mechanism of Action:
- Gentian violet works by binding to the DNA of bacteria and fungi, disrupting their replication and growth.
- It also has a drying effect on the skin, which helps to reduce moisture and inhibit the growth of microorganisms.
3. Uses:
- Gentian violet is primarily used for the treatment of skin infections such as fungal infections, bacterial infections, and yeast infections.
- It is commonly used to treat conditions like oral thrush, diaper rash, and vaginal yeast infections.
- It can also be used for the prevention of infection in minor cuts, scrapes, and burns.
4. Application:
- Gentian violet is typically applied topically to the affected area.
- It is available in various formulations, including ointments, creams, and solutions.
- The affected area should be cleaned and dried before applying the dye.
- It is important to follow the instructions provided by the healthcare professional or the product label for proper application and dosage.
5. Precautions:
- Gentian violet may cause staining of the skin, clothing, and other surfaces it comes into contact with. It is important to use protective measures like gloves and avoid contact with clothing or furniture.
- It may cause skin irritation or allergic reactions in some individuals. If any adverse reactions occur, it is advisable to discontinue use and consult a healthcare professional.
In conclusion, gentian violet is a commonly used antibacterial dye for the treatment of skin infections. It possesses strong antibacterial and antifungal properties and is effective against a wide range of microorganisms. However, it is important to follow proper application techniques and precautions to avoid staining and potential adverse reactions.

Introduction:
The human organ transplantation act in India was established to regulate the removal, storage, and transplantation of human organs for therapeutic purposes. It was enacted to prevent commercialization and illegal trade of organs and ensure ethical practices in organ transplantation.
Detailed Explanation:
The human organ transplantation act was passed in India in the year 1995. Here are some key points regarding the act:
1. Purpose:
- The act aims to regulate the removal, storage, and transplantation of human organs.
- It prohibits the commercialization of organs and promotes altruistic organ donation.
2. Provisions:
- The act defines various terms related to organ transplantation, such as 'brain death,' 'donor,' 'hospital,' etc.
- It establishes the National Organ and Tissue Transplant Organization (NOTTO) and State Organ and Tissue Transplant Organization (SOTTO) to oversee transplantation activities.
3. Consent and Authorization:
- The act requires explicit consent from the donor or their legal representative for organ transplantation.
- It mandates the maintenance of an organ donor registry to facilitate the process.
4. Punishments and Penalties:
- The act imposes strict punishments, including imprisonment and fines, for illegal organ transplantation and trade.
- It also specifies penalties for non-compliance with the provisions of the act.
5. Amendments:
- The act has undergone amendments over the years to address emerging issues and challenges related to organ transplantation.
Conclusion:
The human organ transplantation act came into existence in India in 1995. It has been instrumental in regulating organ transplantation activities, preventing illegal organ trade, and promoting ethical practices in the country. The act has helped in providing a legal framework to ensure the proper and transparent transplantation of organs for therapeutic purposes.

Wonder Crop with High Protein Content: Spirulina
Spirulina is the algae that is considered a wonder crop due to its high protein content. It contains approximately 70% protein, which is even higher than soybean. Here is a detailed explanation of why Spirulina is a superior source of protein:
1. Chlorella:
- Chlorella is a type of algae that is rich in nutrients and protein.
- It contains about 50-60% protein content, which is lower than Spirulina.
2. Dunaliella:
- Dunaliella is a type of algae that is known for its high beta-carotene content.
- While it is a good source of nutrients, it has a lower protein content compared to Spirulina.
3. Scenedesmus:
- Scenedesmus is a genus of green algae that is commonly found in freshwater.
- It has a moderate protein content, but it is not as high as Spirulina.
4. Spirulina:
- Spirulina is a blue-green algae that is cultivated and consumed as a dietary supplement.
- It is a complete protein source, meaning it contains all essential amino acids required by the human body.
- Its protein content is approximately 70%, making it an excellent source of protein.
- Additionally, Spirulina is rich in vitamins, minerals, and antioxidants, providing various health benefits.
In conclusion, among the given options, Spirulina is the algae that stands out as a wonder crop with the highest protein content, exceeding that of soybean. Its impressive protein content, along with its nutritional profile, makes it a popular choice for supplementation and as a protein source in vegetarian and vegan diets.

Eugenics: The Science of Human Variation and Heredity
Eugenics is the science that deals with human variations and heredity, with the aim of improving the human race. It focuses on understanding, controlling, and manipulating the genetic composition of populations to promote desirable traits and eliminate undesirable ones. Here is a detailed explanation of eugenics as a science:
1. Definition and Purpose:
- Eugenics is a field of study that examines how human traits are inherited and aims to improve the genetic quality of the human population.
- Its goal is to promote the reproduction of individuals with favorable traits while discouraging or preventing the reproduction of those with unfavorable traits.
2. Historical Context:
- The concept of eugenics emerged in the late 19th and early 20th centuries, influenced by ideas of selective breeding from the field of animal husbandry.
- It gained popularity during a time when scientific advancements were being made in genetics and the understanding of heredity.
3. Key Principles:
- Selective Breeding: Eugenics advocates for encouraging individuals with desirable traits to reproduce, thus increasing the prevalence of those traits in future generations.
- Sterilization: It has also involved the forced sterilization of individuals considered "unfit" to prevent them from passing on their undesirable traits.
- Restrictive Immigration Policies: Eugenicists have promoted immigration policies that aim to limit the entry of individuals deemed to have undesirable traits.
4. Ethical Concerns and Controversies:
- Eugenics has been heavily criticized for its association with racist ideologies and its historical implementation in the form of forced sterilizations and other human rights abuses.
- The concept of eugenics raises ethical questions regarding individual autonomy, discrimination, and the potential for abuse.
5. Modern Understanding:
- While the term "eugenics" is now often associated with negative connotations, the study of human genetics and heredity continues to be a significant field of scientific research.
- Modern genetics focuses on understanding and treating genetic disorders, improving medical interventions, and advancing our understanding of human biology.
In conclusion, eugenics as a science deals with human variations and heredity with the intention of improving the human race. However, it is important to consider the historical context, ethical concerns, and controversies associated with this field of study.

The part of poppy plant which yields opium is the unripe fruits.
Opium is a highly addictive narcotic drug derived from the opium poppy plant, scientifically known as Papaver somniferum. The plant contains various parts, but it is the unripe fruits that yield opium. Here is a detailed explanation:
1. Opium Poppy Plant:
- The opium poppy plant is an annual flowering plant that belongs to the Papaveraceae family.
- It is primarily grown in countries like Afghanistan, India, and Myanmar for its opium production.
2. Morphine and Codeine:
- Opium contains several alkaloids, including morphine and codeine, which are potent pain relievers and central nervous system depressants.
- These alkaloids are present in the latex or sap that is obtained from the unripe fruits of the poppy plant.
3. Opium Production Process:
- To obtain opium, the unripe fruits of the poppy plant are incised or scored with a sharp blade.
- This process allows the sap to ooze out from the fruits, which is then collected.
- The sap is initially a milky white liquid but turns brown when exposed to air due to oxidation.
4. Opium Processing:
- After collection, the opium sap undergoes a processing method called "lancing."
- The sap is boiled, dried, and further processed to form a brownish-black sticky substance known as raw opium.
5. Uses of Opium:
- Opium has been used for centuries as a painkiller, sedative, and recreational drug.
- It is also the primary source for the production of other drugs like heroin, morphine, and codeine.
In conclusion, the unripe fruits of the poppy plant are responsible for yielding opium. The sap obtained from these fruits contains alkaloids like morphine and codeine, which are used for various medicinal and recreational purposes.

Introduction:
Vitamin A is a fat-soluble vitamin that is essential for various physiological functions in the body. It plays a crucial role in maintaining good vision, supporting the immune system, and promoting healthy skin.
Vitamin A as Retinol:
- Vitamin A is commonly known as retinol, which is a type of preformed vitamin A.
- Retinol is the active form of vitamin A that is found in animal-based foods such as liver, eggs, and dairy products.
- It is easily absorbed by the body and can be stored in the liver for future use.
Vitamin A as Ascorbic Acid:
- Ascorbic acid, also known as vitamin C, is a different vitamin altogether and is not synonymous with vitamin A.
- Vitamin C is a water-soluble vitamin that is found in fruits and vegetables like oranges, strawberries, and broccoli.
- It is essential for collagen synthesis, wound healing, and immune function.
Vitamin A as Thiamine:
- Thiamine, also known as vitamin B1, is another distinct vitamin and not the same as vitamin A.
- Vitamin B1 is a water-soluble vitamin that is involved in energy metabolism and nerve function.
- It can be found in foods like whole grains, legumes, and pork.
Vitamin A as Riboflavin:
- Riboflavin, also known as vitamin B2, is yet another separate vitamin and not vitamin A.
- Vitamin B2 is a water-soluble vitamin that is essential for energy production and the metabolism of fats, carbohydrates, and proteins.
- It is present in foods like milk, yogurt, eggs, and green leafy vegetables.
Conclusion:
Vitamin A is commonly known as retinol, not ascorbic acid (vitamin C), thiamine (vitamin B1), or riboflavin (vitamin B2). It is important to understand the different vitamins and their functions to ensure a balanced and healthy diet.

The folding of the leaf lobes of the Venus flag trap is a response to changing water pressure.


The Venus flytrap is a carnivorous plant that uses its specialized leaves to capture and digest insects. The folding of the leaf lobes is an important mechanism that allows the plant to trap its prey effectively. This folding response is triggered by the stimulation of sensory hairs on the surface of the leaf lobes.
Here's a detailed explanation:
1. Sensory Hairs:
- The Venus flytrap has tiny sensory hairs on the inner surface of its leaf lobes.
- These hairs are triggered when an insect comes into contact with them.
2. Stimulation:
- When an insect touches the sensory hairs, it stimulates an electrical signal in the plant.
- This signal is transmitted to cells in the leaf lobes, initiating a response.
3. Water Pressure:
- The folding response of the leaf lobes of the Venus flytrap is a result of changing water pressure within the cells.
- The electrical signal triggers an influx of water into the cells of the leaf lobes.
4. Turgor Pressure:
- The increased water pressure causes the cells to become turgid, creating a rigid structure.
- This turgor pressure is what causes the leaf lobes to fold inward, trapping the insect.
5. Enzyme Secretion and Digestion:
- Once the prey is trapped, the Venus flytrap secretes digestive enzymes to break down the insect.
- The nutrients from the digested prey are then absorbed by the plant to support its growth.
In conclusion, the folding of the leaf lobes of the Venus flytrap is a response to changing water pressure within the cells. This mechanism allows the plant to efficiently capture and digest insects for its nutrient requirements.

Answer:
The correct answer is B: Isabgol.
Explanation:
Isabgol, also known as psyllium husk, is a herb that is widely used in the treatment of various chronic dysentery conditions. It is known for its therapeutic properties and has been used in traditional medicine for centuries.
Here are some key points about Isabgol and its role in the treatment of chronic dysentery:
What is Isabgol?
- Isabgol is derived from the seeds of the plant Plantago ovata.
- It contains high amounts of soluble fiber and mucilage, which help in relieving digestive issues.
Role in the treatment of chronic dysentery:
- Isabgol acts as a natural laxative, promoting healthy bowel movements and relieving constipation.
- It helps in regulating the bowel movements by adding bulk to the stool and easing its passage.
- The mucilage present in Isabgol forms a protective layer on the intestinal lining, reducing inflammation and irritation.
- Isabgol also absorbs excess water in the intestine, helping in the treatment of diarrhea associated with chronic dysentery.
- It has a soothing effect on the gastrointestinal tract, reducing pain and discomfort.
Other benefits of Isabgol:
- Isabgol can also be used in the treatment of other digestive disorders such as irritable bowel syndrome (IBS) and acid reflux.
- It helps in maintaining healthy cholesterol levels and controlling blood sugar levels.
- Isabgol is also known to aid in weight management by promoting a feeling of fullness and reducing appetite.
In conclusion, Isabgol is an important herb in the treatment of chronic dysentery due to its laxative, anti-inflammatory, and soothing properties. It is widely used to relieve constipation, regulate bowel movements, and reduce inflammation in the gastrointestinal tract.