Biology Mock Test- 2 - Class 10 MCQ

Pair of ducts carrying sperms from testis:

• Vas Deferens: This is the correct answer. Vas deferens is a pair of ducts that carry sperms from the testes to the urethra.


• Fallopian Tubes: Fallopian tubes are part of the female reproductive system and are not involved in carrying sperms from the testes.


• Oviduct: Oviduct is another name for the fallopian tube and does not carry sperms from the testes.


• Urethra: Urethra is the tube through which urine leaves the body and is not involved in carrying sperms from the testes.

Therefore, the correct pair of ducts arising from the testis that carry sperms is the vas deferens. It is essential for the transportation of sperms from the testes to the urethra for ejaculation.

Offspring exhibit similarities as well as variation from parents.

Correct Statement about Receptors:

• Gustatory receptors detect taste while olfactory receptors detect smell: This statement is correct. Gustatory receptors are responsible for detecting taste, while olfactory receptors are responsible for detecting smell.

Therefore, option A is the correct statement about receptors.

The question asks which action is not a natural reflex. The correct answer is salivation at the sight of food. Here's why:

• Knee-jerk, blinking due to strong light, and sneezing are all natural reflexes. They occur automatically without conscious thought.
• However, salivation at the sight of food is not a true reflex. It is a conditioned response where the brain anticipates eating and triggers salivation.

The correct answer is d

According to immunity theory, ageing is associated with the disappearance of the thymus gland by the late middle age in man and replaced by fat. It causes a weakening in the defense mechanisms of the body and in the course of time, leads to a large-scale decay and destruction of cells and tissues.

Explanation:

• Wild cabbage: Wild cabbage is the original ancestor plant that has evolved into different varieties like cabbage, broccoli, and cauliflower.



• Artificial selection: The process of artificial selection, also known as selective breeding, involves humans selecting and breeding plants with desired traits to develop new varieties. In the case of cabbage, broccoli, and cauliflower, humans have selectively bred wild cabbage plants with specific characteristics such as size, taste, and appearance to create these new varieties.



• Genetic drift: Genetic drift is a random process that can lead to changes in the gene pool of a population. While genetic drift can play a role in evolution, it is not the primary mechanism responsible for the development of new cabbage varieties.



• Natural selection: Natural selection is the process by which organisms with advantageous traits are more likely to survive and reproduce, leading to the evolution of populations over time. While natural selection does play a role in the adaptation of wild cabbage plants to their environment, it is not the primary mechanism responsible for the development of new cabbage varieties.



• Reproductive isolation: Reproductive isolation is a mechanism that prevents different species from interbreeding. While reproductive isolation can lead to the formation of new species, it is not the primary mechanism responsible for the development of new cabbage varieties.

Explanation of the correct option: C.

1. According to the Mendel's first law of inheritance or law of dominance, the hybrid offspring produced will only inherit the dominant trait in the phenotype.
2. The alleles that are suppressed are known as recessive traits while that determines the trait are known as dominant traits.
3. A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because tallness is the dominant trait.
4. Thus, tallness is the dominant trait.

The carbon dioxide is excreted out from the body through its moist skin by the process of diffusion. The nitrogenous wastes are excreted out of the body by special excretory organs called nephridia.

Urea is produced in the liver and is metabolite of amino acids. Ammonium ions are formed in the break down of smino acids. Some are used in the Biosynthesis of nitrogen compounds. Excess ammonium ions are converted to urea. 

Non-biodegradable substances:

• Nylon: Nylon is a synthetic polymer that is not easily broken down by natural processes. It takes hundreds of years for nylon to decompose, making it non-biodegradable.

Biodegradable substances:

• Tea leaves: Tea leaves are organic materials that can be easily decomposed by bacteria, fungi, and other microorganisms. They are biodegradable and contribute to the natural nutrient cycle.


• Remains of animals: Animal remains, such as bones and flesh, are also organic materials that can be broken down by natural processes. They are biodegradable and play a role in the decomposition and recycling of nutrients in ecosystems.


• Fleece of sheep: Fleece, which is the wool obtained from sheep, is a natural fiber that can be broken down by microorganisms over time. It is biodegradable and does not contribute to long-term environmental pollution.

In conclusion, the non-biodegradable substance among the given options is nylon. It is a synthetic material that takes a long time to decompose, leading to potential environmental pollution if not properly disposed of.

Like other greenhouse gases, nitrous oxide absorbs radiation and traps heat in the atmosphere, where it can live for an average of 114 years, according to the EPA.

Explanation:

• How strong it is compared to other individuals of the same species: Strength is just one aspect of an organism's ability to survive. Natural selection is not solely based on physical strength.



• How much food and resources it is able to gather for its offspring: While the ability to gather resources is important for survival, it is not the only factor considered in natural selection.



• The ability to adapt to the environment in the niche it occupies: This statement best describes an organism because adaptation to the environment is crucial for survival. Organisms that can adapt to changes in their environment are more likely to survive and pass on their genes.



• The number of fertile offspring it has: The number of offspring an organism has is important for the continuation of the species, but it is not the sole factor in natural selection.

Therefore, the ability to adapt to the environment in the niche it occupies is the most accurate description of an organism in the context of natural selection or 'survival of the fittest'.

Explanation:

• Sex determination: The sex of a child is determined by the combination of sex chromosomes inherited from both parents.


• X chromosome inheritance: In humans, females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).


• Zygote with X chromosome from father: If a zygote receives an X chromosome from the father, it will have one X chromosome from the mother and one X chromosome from the father (XX).


• Development into female: A zygote with two X chromosomes (XX) will develop into a female.


• Conclusion: Therefore, a zygote with an X chromosome inherited from the father will develop into a female.

Function(s) of the liver in excretion:
- Deamination and urea formation: The liver plays a crucial role in the metabolism of amino acids. It removes the amino group (-NH2) from amino acids through a process called deamination, converting them into ammonia (NH3). The liver then combines ammonia with carbon dioxide to form urea, which is less toxic and can be safely excreted in urine by the kidneys.
- Elimination of haemoglobin and bile salts: The liver is responsible for breaking down old and damaged red blood cells. During this process, the haemoglobin component of these cells is converted into bilirubin, a waste product. The liver then conjugates bilirubin with other substances to form bile salts, which are excreted into the bile and eventually eliminated from the body through feces.
- Inactivation of chemicals after their role is over: The liver plays a crucial role in the detoxification and inactivation of various substances, including drugs, alcohol, and environmental toxins. It accomplishes this through a series of enzymatic reactions that modify these substances into less harmful or more easily excretable forms.
Therefore, all of the mentioned functions (deamination and urea formation, elimination of haemoglobin and bile salts, inactivation of chemicals after their role is over) are performed by the liver in excretion. Hence, the correct answer is D: All the three mentioned above.

Active transport can be seen in the kidneys, at the Reabsorption stage in the nephrons. Along the nephron, a large network of capillaries surround the tubules that carry the waste. Substances that the body needs from the waste that can be
 re- used  are  reabsorbed into the blood stream.

Micro-organisms belong to the group of decomposers.

• Micro-organisms are small, single-celled organisms that are not visible to the naked eye.


• They play a crucial role in the ecosystem by breaking down organic matter and recycling nutrients.


• Decomposers, such as bacteria and fungi, are responsible for the process of decomposition.


• Decomposition is the breakdown of dead plants and animals into simpler substances, which can then be used by other organisms.


• Micro-organisms secrete enzymes that help in the breakdown of complex organic molecules into simpler compounds.


• They obtain their energy by breaking down organic matter.


• Micro-organisms are found in various environments, such as soil, water, and even inside the bodies of other organisms.


• They are essential for the nutrient cycling in ecosystems and help in maintaining the balance of nature.


• Examples of micro-organisms that act as decomposers include bacteria, fungi, and certain types of protozoa.

In conclusion, micro-organisms are a group of decomposers that play a vital role in the ecosystem by breaking down organic matter and recycling nutrients. They are found in various environments and are essential for maintaining the balance of nature.

Function of an ecosystem involves:
The function of an ecosystem is a complex process that involves various components working together to sustain life. The main functions of an ecosystem include:
1. Energy flow:
- Ecosystems are powered by the flow of energy through food chains and food webs.
- Producers (plants) convert sunlight into chemical energy through photosynthesis.
- Consumers obtain energy by consuming other organisms.
- Decomposers break down organic matter and release energy.
2. Nutrient movement:
- Nutrients are essential for the growth and development of organisms in an ecosystem.
- Nutrients are cycled through biogeochemical cycles, such as the carbon, nitrogen, and phosphorus cycles.
- Producers take up nutrients from the environment and incorporate them into their tissues.
- Consumers obtain nutrients by consuming other organisms.
- Decomposers break down organic matter and release nutrients back into the environment.
3. Interactions and relationships:
- Ecosystems are composed of numerous species that interact with each other.
- Predation, competition, symbiosis, and mutualism are common interactions in an ecosystem.
- These interactions help maintain the balance and stability of the ecosystem.
4. Ecological services:
- Ecosystems provide numerous benefits to humans and other organisms.
- They regulate climate, purify air and water, and provide habitats for various species.
- Ecosystems also provide resources such as food, timber, and medicines.
5. Biodiversity conservation:
- Ecosystems support a wide range of species, each with its own role and contribution.
- Conserving ecosystems is crucial for maintaining biodiversity and preventing species extinction.
In conclusion, the function of an ecosystem involves energy flow, nutrient movement, interactions and relationships, ecological services, and biodiversity conservation. These functions are interconnected and essential for the sustainability of life on Earth.

organism prepare their own food with the help of simple inorganic materials like CO₂,H₂O in sunlight with the help of chlorophyll. Thus, it doesn’t involve oxygen in the process.

Cellular respiration allows organisms to use energy stored in the chemical bonds of glucose. The energy in glucose is used to produce  ATP. Cells use ATP to supply their energy needs. Cellular respiration is therefore a process in which the energy in glucose is transferred to ATP.

Cellular respiration is the process of breaking sugar into a form that the cell can use as energy. This happens in all forms of life. Cellular respiration takes in food and uses it to create ATP, a chemical which the cell uses for energy. Usually, this process uses oxygen, and is called aerobic respiration.

An underground stem axis with swollen base and enclosed by dry scale like leaves is called as corm. The corm is a solid modified stem that has few fleshy leaves. It is a swollen stem which stores food to survive winter, summer  drought and heat.

The waste products of a plant are carbon dioxide, water and oxygen. While carbon dioxide and water vapour are waste products of respiration, oxygen is a waste product of photosynthesis. 

Plants produce carbon dioxide and water as respiratory waste products. In green plants, the carbon dioxide released during respiration gets utilised during photosynthesis. Oxygen is a waste product generated during photosynthesis and exists through stomata, root cellar Walls and other routes. Plants can get rid of excess water by transpiration and guttation.

Male produces two types of sperms 50% sperms have X chromosome and rest 50% have Y chromosome. If sperm having X chromosome fertilises ovum the sex of child will be female and in case sperm having Y chromosome fertilises the egg the child will be male.

Plant is easily grown in garden soil so it can be easily used for experiment. 
Mendels experiment is to prove that pure tall  and pure dwarf give different types of progency. So, he have to take a plant which have distinct phenotype. Therefore he used pea.

Because in alveoli( richly supplied with blood vessels), where oxygenated blood is present, is absorbed by haemoglobin, present in the RBC(Red Blood Cell). With the help of haemoglobin, the oxygenated blood is diffused in the whole body. Where on the other side, deoxygenated blood, which is present in the plasma, is reached to the alveoli and it absorbs by our lungs then finally the deoxygenated blood is exhaled by our nostrils. This is how alveoli helps for respiration with the help of diffusion in our lungs.

the hemoglobin increases the oxygen carrying capacity of blood. In humans and most other vertebrates, the most common respiratory pigment is a protein called hemoglobin.

Haemoglobin is the iron containing protein found in red blood cells. It is responsible for the transportation of oxygen and carbon dioxide. It consists of four protein chains and each chain has a haem group attached to it. Each haem group has an iron molecule. The oxygen binds to the iron molecule. Since there are four iron molecules, each haemoglobin is capable of carrying four oxygen molecules.

In the context of evolution, the use of feathers by birds for flying means that birds have evolved from reptiles. Dinosaurs had feathers but could not fly using them. Birds later adapted the feathers for flight. Since dinosaurs were reptiles, this means that birds have evolved from them.

Role of Fossil: Provides missing link between the species/who has evolved from whom. They tell us about prehistoric organisms. Also, it helps in establishing the time period in which organisms lived.