Frog Test - Zoology, Class 11 - Class 11 MCQ

Functional kidney of frog is:
Mesonephric
Explanation:
The frog has three types of kidneys in its developmental stages: pronephric, mesonephric, and metanephric. However, the functional kidney in adult frogs is the mesonephric kidney.
Here is a detailed explanation of each type of kidney found in frogs:
1. Pronephric Kidney:
- This is the simplest and most primitive kidney found in the early development stages of the frog.
- It consists of a series of nephrons that are responsible for the filtration of waste products from the blood and excretion of urine.
- The pronephric kidney is non-functional in adult frogs and eventually degenerates.
2. Mesonephric Kidney:
- The mesonephric kidney develops after the degeneration of the pronephric kidney.
- It is the functional kidney in adult frogs.
- The mesonephric kidney is responsible for maintaining water balance, excreting waste products, and regulating electrolyte levels in the frog's body.
- It consists of numerous nephrons that filter the blood and produce urine.
3. Metanephric Kidney:
- The metanephric kidney is the final kidney stage in frog development.
- It develops from a bud called the ureteric bud and the metanephric mesoderm.
- In some frog species, such as the African clawed frog, the metanephric kidney becomes the functional kidney in the adult stage.
- However, in most frog species, including the common frog, the mesonephric kidney remains the functional kidney throughout adulthood.
Therefore, the functional kidney in adult frogs is the mesonephric kidney.

Introduction:
Bidder's canal, also known as the Bidder's organ, is a reproductive structure found in male frogs. It is a vestigial structure that serves as a remnant of the female reproductive system.
Location:
Bidder's canal is found in the kidney of the frog.
Explanation:
The kidney in male frogs has a specialized structure called the Bidder's canal. It is a duct that is lined with ciliated epithelium and connects the testes to the cloaca. The cloaca is a common opening for the digestive, urinary, and reproductive systems in amphibians.
Function:
The Bidder's canal serves as a passage for the sperm to reach the cloaca during reproduction. It allows the transfer of sperm from the testes to the cloaca, where it can be released during mating.
Developmental Significance:
The presence of Bidder's canal in male frogs is an example of evolutionary remnants. In female frogs, the Bidder's canal develops into the oviduct, which is a part of the female reproductive system responsible for the transport of eggs. However, in males, this structure undergoes regression and becomes non-functional.
Conclusion:
In conclusion, Bidder's canal in frogs is found in the kidney. It serves as a vestigial structure that connects the testes to the cloaca and allows the transfer of sperm during reproduction. Its presence in male frogs is an example of evolutionary remnants.

Function of Kidney in Frog:
The kidney in a frog serves several important functions in maintaining the overall health and well-being of the organism. These functions include:
1. Excretion:
- The primary function of the frog's kidney is to remove waste products from the bloodstream.
- It filters metabolic waste, such as urea, uric acid, and ammonia, from the blood and converts them into urine.
- This helps in maintaining the proper balance of water and solutes in the body.
2. Osmoregulation:
- The kidney plays a crucial role in regulating the osmotic balance of the frog's body.
- It helps in maintaining the proper concentration of salts and other solutes in the body fluids.
- The kidney adjusts the amount of water that is reabsorbed back into the body or excreted as urine, depending on the frog's hydration status.
3. Haemopoiesis in larva:
- In the larval stage of the frog (tadpole), the kidney also functions as a site for the production of red blood cells (haemopoiesis).
- The kidney contains specialized cells called interrenal cells, which produce erythropoietin, a hormone that stimulates the production of red blood cells.
4. Regulation of pH:
- The kidney helps in maintaining the acid-base balance of the frog's body by regulating the excretion of hydrogen ions and bicarbonate ions.
5. Water balance:
- The kidney controls the amount of water reabsorbed by the body, helping to regulate the overall water balance.
- It conserves water when the frog is in a dehydrated state and excretes excess water when the frog is in a hydrated state.
In conclusion, the kidney in a frog performs multiple functions, including excretion, osmoregulation, haemopoiesis in larva, regulation of pH, and water balance. These functions are essential for maintaining the proper physiological balance and overall health of the organism.

Male Frog Ureter Transfer:
In male frogs, the ureters play a crucial role in the transfer of substances. Let's explore the options provided and determine which one(s) are correct:
Option A: Urine
- Male frogs do produce urine, which is a waste product filtered from their blood by the kidneys.
- However, the ureters in male frogs are not involved in the transfer of urine.
Option B: Sperms
- The male frogs transfer their sperm to the female during reproduction.
- The sperm is not transferred through the ureters, but rather through a specialized structure called the cloaca.
Option C: Both 1 and 2
- This option implies that both urine and sperm are transferred through the ureters, which is incorrect.
- As mentioned earlier, urine is not transferred through the ureters in male frogs.
- While sperm is involved in reproduction, it is not transferred through the ureters either.
Option D: None
- This option implies that neither urine nor sperm is transferred through the ureters, which is correct.
- The ureters in male frogs do not play a role in the transfer of urine or sperm.
Therefore, the correct answer is Option D: None.

Introduction:
In frogs, the kidney consists of two main regions - the cortex and the medulla. These regions play important roles in the filtration and excretion of waste materials from the body.
Cortex:
- The cortex is the outer region of the frog kidney.
- It contains numerous nephrons, which are the functional units of the kidney responsible for filtration and reabsorption.
- The cortex is involved in the initial filtration of blood, where waste products and excess water are removed from the blood.
- It is also responsible for reabsorbing essential nutrients and ions back into the blood.
Medulla:
- The medulla is the inner region of the frog kidney.
- It contains collecting ducts, which receive the filtrate from the nephrons in the cortex.
- The medulla is responsible for further concentration and modification of the filtrate.
- It helps in reabsorbing additional water and ions, thus maintaining the body's water and electrolyte balance.
Answer:
Based on the given options, the correct answer is option C: Absent.

Explanation:
In frogs, the kidneys are present and serve the same function as in other vertebrates. Here is a detailed explanation of the position of the kidneys in frogs:
Anatomy of Frog Kidneys:
- The kidneys in frogs are bean-shaped organs located on either side of the vertebral column.
- Each kidney is positioned slightly posterior to the liver and slightly anterior to the hind limbs.
- The kidneys are retroperitoneal, which means they are located behind the peritoneal cavity and are surrounded by connective tissue and fat.
- The adrenal glands are attached to the cranial end of each kidney.
Identical Position:
- The kidneys in frogs are identical in position, meaning they are found on both sides of the body in the same relative location.
- This is true for both male and female frogs.
Function of Frog Kidneys:
- The kidneys in frogs are responsible for filtering waste products and excess water from the blood.
- They maintain the balance of electrolytes, water, and acid-base levels in the body.
- The filtered waste products are excreted as urine.
Conclusion:
- The kidneys in frogs are identical in position on both sides of the body.
- They play a crucial role in maintaining the overall health and homeostasis of the frog's body.

Pyramids in Kidney of Frog
The kidney of a frog consists of specialized structures called nephrons, which are responsible for filtering waste products from the blood and producing urine. These nephrons contain pyramid-like structures known as renal pyramids. Here is a detailed explanation of the number of pyramids present in the kidney of a frog:
Anatomy of Frog Kidney:
- The kidney of a frog is a bean-shaped organ located in the abdominal cavity.
- It consists of two distinct regions: the outer cortex and the inner medulla.
- The cortex is the outer layer, while the medulla is the inner layer.
Renal Pyramids:
- The renal pyramids are triangular structures located in the medulla of the frog's kidney.
- These pyramids are composed of tiny tubes called nephrons, which are the functional units of the kidney.
- Nephrons play a crucial role in filtering waste materials and regulating the water balance in the body.
Number of Pyramids:
- The number of renal pyramids in the kidney of a frog varies depending on the species and individual frog.
- Generally, frogs have a varying number of renal pyramids in each kidney.
- However, in most cases, the number of pyramids in a frog's kidney is absent (Option D).
- This means that frogs do not have distinct pyramids in their kidneys like some other animals do.
Conclusion:
In conclusion, the number of pyramids in the kidney of a frog is absent (Option D). Frogs do not have renal pyramids as a prominent feature in their kidneys. It is important to note that the absence of pyramids in the frog's kidney is a characteristic specific to this species and should not be generalized to all animals.

Teeth of Frog
Types of Frog Teeth:
- Acrodont: This is the correct answer. Acrodont teeth are found in frogs, where the teeth are attached to the top of the jawbone.
- Pleurodont: This is not the correct answer. Pleurodont teeth are found in reptiles, where the teeth are attached to the inner side of the jawbone.
- Thecodont: This is not the correct answer. Thecodont teeth are found in crocodiles, where the teeth are embedded in sockets in the jawbone.
- Heterodont: This is not the correct answer. Heterodont teeth are found in mammals, where different types of teeth serve different functions.
In conclusion, the teeth of a frog are acrodont in nature, meaning they are attached to the top of the jawbone.

The lower jaw being toothless is a characteristic feature of certain animals. Let's analyze each option to determine which one fits the given description.
A: Cockroach
- Cockroaches have a lower jaw called the mandible, which is not toothless but contains teeth-like structures called mandibular spines.
- Therefore, option A is not the correct answer.
B: Man
- Humans have a lower jaw that is not toothless. It contains two sets of teeth, the deciduous teeth (baby teeth) and the permanent teeth.
- Therefore, option B is not the correct answer.
C: Rabbit
- Rabbits have a lower jaw that is toothless. They have a unique dental structure called "peg teeth" or "rodent incisors" located on the upper jaw.
- Therefore, option C is a possible correct answer.
D: Frog
- Frogs have a lower jaw that is toothless. They possess a specialized tongue and unique mouth structures for catching and consuming prey.
- Therefore, option D is a possible correct answer.
Conclusion:
Based on the analysis, both options C (Rabbit) and D (Frog) have toothless lower jaws. Therefore, the correct answer is option D, Frog.

The venous system of frog differs from that of rabbit in the presence of:
- Hepatic portal system: The hepatic portal system is present in the frog's venous system but not in the rabbit's. This system allows blood from the digestive organs to be transported directly to the liver before returning to the heart. It helps in the detoxification and processing of nutrients absorbed from the digestive system.
- Renal portal system: The renal portal system is present in the frog's venous system but not in the rabbit's. This system allows blood from the hind limbs to pass through the kidneys before returning to the heart. It helps in the excretion of waste products and regulates the water and electrolyte balance in the frog.
- Hepatic vein: The presence of the hepatic vein is common in both the frog and rabbit's venous system. It carries blood from the liver to the vena cava, which then returns the blood to the heart.
- Three vena cava: The presence of three vena cava is common in both the frog and rabbit's venous system. The three vena cava are the posterior vena cava, anterior vena cava, and hepatic portal vein. They collect deoxygenated blood from different parts of the body and return it to the heart.
In summary, the main difference between the venous system of a frog and a rabbit lies in the presence of the hepatic portal system and renal portal system in the frog, which are absent in the rabbit.

Three Chambered Heart
A three-chambered heart refers to a type of circulatory system found in certain animals, where the heart is divided into three chambers. This type of heart allows for a partial separation of oxygenated and deoxygenated blood, but not a complete separation like in a four-chambered heart.
The animals that have a three-chambered heart are:
Frog:
- Frogs belong to the group of amphibians, and they have a three-chambered heart.
- The heart consists of two atria and one ventricle.
- The left atrium receives oxygenated blood from the lungs, while the right atrium receives deoxygenated blood from the body.
- The ventricle then pumps the mixed blood to various parts of the body.
Snake:
- Snakes, which are reptiles, also have a three-chambered heart.
- Like the frog, the snake's heart consists of two atria and one ventricle.
- The left atrium receives oxygenated blood from the lungs, while the right atrium receives deoxygenated blood from the body.
- The ventricle then pumps the mixed blood to different parts of the body.
Tortoise:
- Tortoises, which are reptiles, have a three-chambered heart as well.
- The heart consists of two atria and one ventricle.
- The left atrium receives oxygenated blood from the lungs, while the right atrium receives deoxygenated blood from the body.
- The ventricle then pumps the mixed blood to various parts of the body.
Butterfly:
- Butterflies, on the other hand, do not have a three-chambered heart.
- They have an open circulatory system where the heart pumps hemolymph (a fluid similar to blood) into the body cavity.
- The hemolymph directly bathes the organs and tissues, allowing for gas exchange.
In conclusion, out of the options given, the animal with a three-chambered heart is the frog (option A). Snakes and tortoises also have a three-chambered heart, while butterflies do not.

Absence of thumb is a feature of:
Option A: Rabbit
- Rabbits have thumbs, so the absence of thumb is not a feature of rabbits.
Option B: Man
- Humans have opposable thumbs, which are essential for our dexterity and ability to grasp objects. Therefore, the absence of thumb is not a feature of humans.
Option C: Frog
- Frogs do not have thumbs. They have long, webbed feet that are adapted for swimming and jumping. The absence of thumb is a feature of frogs.
Option D: Monkey
- Monkeys, like humans, have opposable thumbs. Their thumbs allow them to grasp and manipulate objects. Therefore, the absence of thumb is not a feature of monkeys.
Conclusion:
The correct answer is C: Frog. The absence of thumb is a feature of frogs, as they do not have thumbs like humans and monkeys.

The dorsal part of a frog refers to its upper surface, while the ventral part refers to its lower surface. In the case of a frog, the dorsal part is olive green in color, while the ventral part is uniformly pale yellow.
Here is a detailed explanation of the options given:
Option A: Olivegreen, uniformly pale yellow
- This option correctly describes the color of the frog's dorsal and ventral parts. The frog's dorsal part is olive green, while the ventral part is uniformly pale yellow.
Option B: Olivegreen, uniformly dark yellow
- This option is incorrect as it describes the color of the ventral part as uniformly dark yellow, which is not true. The ventral part is uniformly pale yellow.
Option C: Olivegreen, nonuniformly pale yellow
- This option is incorrect as it describes the color of the ventral part as nonuniformly pale yellow. The ventral part is uniformly pale yellow.
Option D: Olivegreen, nonuniformly dark yellow
- This option is incorrect as it describes the color of the ventral part as nonuniformly dark yellow. The ventral part is uniformly pale yellow.
Therefore, the correct answer is option A: Olivegreen, uniformly pale yellow.

Common Indian bullfrog is:

• Rana tigrina


• Rana essulenta


• Rana silvatica


• Rana goliath

Detailed
The correct answer is Rana tigrina. Here is a detailed explanation:
1. Common Indian bullfrog, also known as Indian bullfrog or Indian bull frog, is a large species of frog found in many parts of India.
2. It belongs to the genus Rana, which includes many species of frogs.
3. The specific scientific name for the Common Indian bullfrog is Rana tigrina.
4. It is a powerful and robust frog, known for its loud croaking sound and extensive jumping ability.
5. The Common Indian bullfrog is characterized by its greenish-brown coloration with darker spots and a white belly.
6. It has a rounded body shape, strong hind legs, and a muscular build.
7. These frogs are typically found near freshwater bodies such as lakes, ponds, and marshes.
8. They are carnivorous and feed on a variety of prey, including insects, small vertebrates, and even other frogs.
9. The breeding season of Common Indian bullfrogs occurs during the monsoon season when they gather in large numbers near water bodies to mate and lay eggs.
10. The tadpoles of these frogs undergo metamorphosis and transform into froglets before becoming adult frogs.
In conclusion, the correct scientific name for the Common Indian bullfrog is Rana tigrina. This species is native to India and is known for its distinctive appearance and behaviors.

Summer Sleep of Frogs - Aestivation

During the summer season, frogs undergo a period of dormancy known as aestivation. Aestivation is the phenomenon where animals, including frogs, adapt to survive in hot and dry conditions.

Why do frogs aestivate during summer?

• Frogs are ectothermic animals, which means their body temperature changes with the environment.


• Hot and dry conditions can lead to dehydration and overheating in frogs.


• Aestivation allows frogs to conserve energy and minimize water loss during the hot summer months.

How do frogs aestivate?

• Frogs find shelter in cool and moist places, such as burrows or under rocks.


• They bury themselves in the soil or mud to create a protective layer against high temperatures and dryness.


• Frogs may also secrete a mucus-like substance that helps maintain moisture and prevent dehydration.


• During aestivation, the metabolic rate of frogs decreases significantly, reducing their need for food and oxygen.

Comparison with Hibernation

• Hibernation is a state of inactivity that occurs during the winter season to conserve energy in animals.


• Aestivation and hibernation are both forms of dormancy, but they occur in different seasons and are triggered by different environmental conditions.


• Hibernation is usually associated with cold temperatures, while aestivation is a response to hot and dry conditions.

In conclusion, the summer sleep of frogs is called aestivation. It is a survival mechanism that allows frogs to conserve energy and minimize water loss during hot and dry conditions. Aestivation is different from hibernation, which occurs during the winter season.

Head of frog:
- The head of a frog is the anterior (front) part of its body.
- It contains various structures such as the eyes, nostrils, mouth, and brain.
Anterior conical part:
- The anterior conical part of the frog's head is referred to as the snout.
- The snout is a pointed, cone-shaped structure located at the front of the head.
Identifying the shape of the frog's head and snout:
- The question asks for the shape of the frog's head and its snout.
- To determine the correct answer, we need to consider the shape of the head and the term used for the anterior conical part.
Answer: B (Triangular, snout)
- The correct answer is B, which states that the head of a frog is triangular and its anterior conical part is called a snout.
- This means that the head of a frog has a triangular shape, and the pointed, cone-shaped structure at the front is referred to as the snout.
Overall, the head of a frog is triangular in shape, and its anterior conical part is known as the snout.

Explanation:
The true statement regarding the frog (Rana tigrina) is option C: poisonous glands are not found on the body of the frog.
Here is a detailed explanation of each statement:
A: Frog is a homeothermal animal
- This statement is false. Frogs are ectothermic animals, which means they cannot regulate their body temperature internally. Instead, they rely on external sources of heat to regulate their body temperature.
B: Frog drinks about 5 litres H2O per day
- This statement is false. While frogs do need to stay hydrated, they do not drink water in the same way that mammals do. They absorb moisture through their skin and by sitting or soaking in water. The amount of water they absorb varies depending on the species and environmental conditions.
C: Poisonous glands are not found on the body of the frog
- This statement is true. Frogs have specialized glands called "poison glands" or "parotoid glands" located behind their eyes and on their back. These glands secrete toxins, which serve as a defense mechanism against predators. However, not all frogs are poisonous, and the presence of these glands varies among different frog species.
D: A very long tail is present in the posterior part of the frog's body
- This statement is false. Frogs do not have a long tail in their adult form. While they do have a tail during their tadpole stage, it is eventually absorbed as they metamorphose into adult frogs.
In conclusion, the true statement regarding the frog (Rana tigrina) is that poisonous glands are not found on the body of the frog.

Frog belong to order:
- Anura is the correct answer.
- Frogs belong to the order Anura, which is one of the three orders of amphibians.
- Anura means "without a tail" in Greek, which describes the characteristic feature of frogs - their lack of a tail as adults.
- The order Anura includes more than 7,000 species of frogs and toads.
- Frogs are found all over the world except in Antarctica.
- They have a unique life cycle, starting as aquatic tadpoles and then metamorphosing into terrestrial adults.
- Frogs are known for their jumping ability and their ability to produce a variety of sounds.
- They have specialized adaptations for living in both aquatic and terrestrial environments.
- Frogs play important roles in ecosystems as both predators and prey, and they also serve as indicators of environmental health.
- Some well-known frog species include the bullfrog, tree frog, and poison dart frog.
Incorrect options:
- Urodela: Urodela is the order that includes salamanders and newts.
- Apoda: Apoda is the order that includes caecilians, which are legless amphibians.
- Caudata: Caudata is another term for the order Urodela, which includes salamanders and newts.

Headers:
- Introduction
- Explanation
Introduction:
Vocal sacs are specialized structures found in certain amphibians, particularly in male frogs. These sacs play an important role in producing and amplifying vocalizations during mating calls.
Explanation:
Vocal sacs are found in male frogs and not in female frogs or any other amphibians. Here is a detailed explanation of why vocal sacs are found only in male frogs:
- Function: The main function of vocal sacs is to amplify the sound produced by the vocal cords. Male frogs use vocalizations to attract females during the mating season. The vocal sacs act as resonating chambers, allowing the sound to resonate and be projected over long distances.
- Structure: Vocal sacs are elastic, thin-walled pouches located on the floor of the mouth. They are connected to the vocal cords and expand when the frog produces a sound. The expansion of the vocal sacs increases the volume and intensity of the sound produced.
- Hormonal Influence: The development and enlargement of vocal sacs in male frogs are controlled by hormones, particularly testosterone. During the breeding season, testosterone levels rise, leading to the growth of vocal sacs and increased vocalization ability.
- Species Variation: It's important to note that not all male frogs have vocal sacs, and the size and structure of vocal sacs can vary among different species. Some species may have large, noticeable vocal sacs, while others may have smaller or less prominent sacs.
In conclusion, vocal sacs are specialized structures found in male frogs. They play a crucial role in producing and amplifying vocalizations, specifically during the mating season. Female frogs and other amphibians do not possess vocal sacs.

The glands present in the skin of frog are:
- Mucous glands: These glands secrete a slimy substance called mucous. Mucous glands are found all over the body of a frog, including the skin. The mucous secreted by these glands helps in keeping the skin moist, protecting it from drying out, and facilitating easy movement in water.
- Poisonous glands: Frogs have specialized glands called poison glands or granular glands. These glands are located on the dorsal side of the frog's skin, particularly on the back. They secrete toxic substances called toxins or poisons. These toxins act as a defense mechanism, deterring predators from attacking the frog. The most well-known poison frog species are the brightly colored ones found in tropical rainforests.
- Sweat glands: Sweat glands are not typically found in the skin of frogs. Sweat glands are more commonly found in mammals, including humans. These glands produce sweat, which helps in regulating body temperature.
- Mammary glands: Mammary glands are specialized glands found in mammals, particularly females. They produce milk for nourishing and feeding the young ones. Frogs do not have mammary glands.
- Sebaceous glands: Sebaceous glands are also not typically found in the skin of frogs. Sebaceous glands are associated with hair follicles in mammals and produce an oily substance called sebum, which helps in lubricating and protecting the skin.
Therefore, the correct answer is A: Mucous and poisonous, as frogs have both mucous glands and poisonous glands in their skin.

Modified Gland into Poison Gland:
The correct answer is B: Pituitary gland.
Explanation:
The pituitary gland is a small pea-sized gland located at the base of the brain. It is often referred to as the "master gland" because it plays a crucial role in regulating and controlling various bodily functions. However, the pituitary gland is not modified into a poison gland.
The sebaceous gland is responsible for producing sebum, an oily substance that helps lubricate the skin and hair. It is not modified into a poison gland.
The parotid gland is the largest of the salivary glands and is responsible for producing saliva. It is not modified into a poison gland.
Therefore, the correct answer is D: None of these. None of the glands mentioned (sebaceous gland, pituitary gland, parotid gland) are modified into a poison gland.

Respiration in a Hibernating Frog:
During hibernation, frogs undergo a period of reduced metabolic activity where their body temperature and oxygen consumption decrease. As a result, their respiration is adapted to meet their reduced energy requirements.
The primary mode of respiration in a hibernating frog is through the skin. This allows the frog to exchange gases (oxygen and carbon dioxide) with the surrounding environment. The skin of a frog is highly vascularized, meaning it contains a network of blood vessels that facilitate gas exchange.
Reasons for Skin Respiration in a Hibernating Frog:

1. Efficient exchange: The skin provides a large surface area for gas exchange, allowing for efficient uptake of oxygen and elimination of carbon dioxide.
2. Reduced energy expenditure: By relying on skin respiration, the frog can conserve energy during hibernation since the use of lungs or other respiratory organs would require more energy.
3. Adaptation to aquatic environment: Many frog species are semi-aquatic or fully aquatic, and their skin is adapted for gas exchange in water. This adaptation is beneficial during hibernation when the frog may be in a moist or aquatic environment.
Other Modes of Respiration:
While skin respiration is the primary mode of respiration in a hibernating frog, other respiratory surfaces may also play a role in gas exchange. These include:
1. Lungs: Frogs have lungs, but during hibernation, their lung activity decreases significantly. This is because the reduced metabolic rate lowers the oxygen demand, and skin respiration is sufficient to meet the oxygen needs.
2. Buccal epithelium: The buccal cavity, which includes the lining of the mouth and throat, can also serve as a respiratory surface. However, during hibernation, the frog's metabolic activity is reduced, and buccal respiration is not the primary mode of gas exchange.
In conclusion, a hibernating frog primarily respires through its skin due to the efficient gas exchange, reduced energy expenditure, and adaptation to an aquatic environment. While the frog has lungs and buccal epithelium that can also facilitate respiration, they are not the primary respiratory organs utilized during hibernation.

Characteristics of frogs:
- Thin, scaleless skin
- Aquatic reproduction
- Cutaneous respiration
Explanation:
- Frogs have a thin, scaleless skin that allows them to absorb water and oxygen directly through their skin.
- Frogs reproduce in water, with females laying eggs and males fertilizing them externally. The eggs develop into tadpoles, which undergo metamorphosis into adult frogs.
- Frogs also have the ability for cutaneous respiration, which means they can breathe through their skin. This is particularly important when they are submerged in water and cannot rely solely on lung respiration.
Conclusion:
The trait that is not characteristic of frogs is:
- Amniote egg. Frogs do not lay amniote eggs, which are characteristic of reptiles and birds. Instead, they lay eggs that develop into aquatic tadpoles.

The absence of a neck in frogs provides them with several advantages that aid in their survival and adaptation to their environment. These advantages include:
1. Efficient catching of prey:
- Frogs have a wide mouth and a strong tongue, which allows them to catch insects and small prey quickly.
- The absence of a neck enables frogs to strike at their prey swiftly and accurately, minimizing the chances of escape.
2. Enhanced respiration:
- Frogs primarily respire through their skin, which is thin and moist, allowing oxygen to diffuse into their bloodstream.
- The absence of a neck ensures that the skin covering the entire body surface is exposed to the air, maximizing oxygen absorption.
3. Improved swimming in water:
- The streamlined body shape of frogs, with no neck, reduces drag in water, enabling them to swim swiftly and navigate efficiently.
- The absence of a neck allows frogs to move their hind legs more freely, generating powerful thrust for swimming.
4. Efficient jumping on the ground:
- Frogs are known for their exceptional jumping ability, which aids in evading predators and capturing prey.
- The lack of a neck allows frogs to have a more compact body structure, facilitating efficient and powerful leg movements for jumping.
In conclusion, the absence of a neck in frogs provides several advantages, including efficient prey capture, enhanced respiration, improved swimming abilities, and efficient jumping on the ground. These adaptations have contributed to the success of frogs as highly adaptable and successful amphibians.

Reasons why a frog lives in water or near water:
1. Respiration:
- Frogs have a specialized respiratory system that allows them to respire through their skin.
- The skin of frogs is thin and moist, which enables the exchange of gases, such as oxygen and carbon dioxide, with the surrounding water.
- Living in or near water ensures a constant supply of oxygen for the frog's respiratory needs.
2. Reproduction:
- Frogs lay their eggs in water, and the eggs hatch into tadpoles.
- Tadpoles are aquatic and require water for their development.
- By living in or near water, frogs ensure the survival of their offspring through the crucial stages of their life cycle.
3. Moisture and Hydration:
- Frogs have permeable skin that easily loses water through evaporation.
- By living in or near water, frogs can keep their skin moist, preventing dehydration and maintaining their physiological functions.
4. Food Source:
- Aquatic environments, such as ponds, lakes, and streams, provide a rich food source for frogs.
- Frogs feed on a variety of organisms, including insects, small fish, worms, and other invertebrates, which are abundant in water habitats.
- Living in or near water allows frogs to easily access their food supply.
5. Camouflage and Protection:
- Many frog species have evolved to have colors and patterns that blend in with their aquatic surroundings.
- This camouflage helps them hide from predators and increases their chances of survival.
- Additionally, being in or near water offers frogs protection from certain predators, as some cannot swim or hunt in aquatic environments effectively.
6. Mobility and Locomotion:
- Frogs have hindlimbs that are adapted for swimming.
- Their hindlimbs are webbed, which allows them to move efficiently through the water and escape from predators.
- Living in or near water provides frogs with the necessary space and resources for their aquatic locomotion.
In conclusion, frogs live in or near water due to their unique adaptations for respiration, reproduction, hydration, access to food, camouflage, protection, and mobility. These factors contribute to their survival and overall success in their aquatic habitats.

Rana tigrina is zoological name of:
The correct answer is A: Frog.
Explanation:
Rana tigrina is the scientific or zoological name of a frog. Let's break down the explanation into bullet points for better understanding:
- Zoological name: It refers to the scientific name given to a particular species. It is used to identify and categorize organisms based on their characteristics and evolutionary relationships.
- Rana tigrina: This is the specific scientific name given to a species of frog commonly known as the Indian bullfrog or tiger frog.
- Frog: Frogs are amphibians belonging to the order Anura. They have unique characteristics such as a moist and permeable skin, long hind legs for jumping, and the ability to lay eggs in water. They undergo metamorphosis, starting as tadpoles and transforming into adults.
- Rana tigrina (frog): The Rana tigrina species is native to the Indian subcontinent and is known for its large size, powerful croaking sound, and distinctive markings.
In conclusion, Rana tigrina is the zoological name for the frog species commonly referred to as the Indian bullfrog or tiger frog.

Explanation:
Introduction:
Frogs are a type of amphibian, which means they have the ability to live both on land and in water. They undergo a metamorphosis during their life cycle, starting as aquatic tadpoles and eventually transforming into terrestrial adults. There are several reasons why frogs belong to the amphibian group.
Tail is not found in it:
- Frogs do not have a tail as adults. They have a shortened tail during their tadpole stage, but it is eventually resorbed as they undergo metamorphosis into frogs.
Lungs are found in it:
- Frogs possess lungs, which allow them to breathe air. They have the ability to extract oxygen from the air and exchange it with carbon dioxide through their lungs.
Its tadpoles are aquatic in nature:
- The life cycle of a frog starts with aquatic tadpoles. These tadpoles have gills and live exclusively in water, obtaining oxygen from the water through their gills.
It lives in water as well as on land:
- Frogs are well-known for their ability to live both in water and on land. They have specialized skin that allows them to absorb water and oxygen directly, which is important for their survival in both environments.
Conclusion:
Based on the above reasons, it is clear that frogs belong to the amphibian group. Their characteristics such as the absence of a tail in adults, the presence of lungs, the aquatic nature of their tadpoles, and their ability to live in both water and land distinguish them as amphibians.

Skull of frog is:
- Tricondylic

Answer: B
Explanation:
Frogs belong to the amphibian group of animals. They have a unique limb structure consisting of four limbs, with each limb having digits. The arrangement of fingers and toes in frogs is as follows:
- Front Limbs (Forelimbs): Frogs have four fingers on their front limbs.
- Hind Limbs (Back limbs): Frogs have five toes on their hind limbs.
Therefore, the correct option is B: four fingers and five toes.
To summarize:
- Front limbs: Four fingers
- Hind limbs: Five toes

Frog Reproduction:
There are four options given for how frogs reproduce: A, B, C, and D. The correct answer is A, which is "in water." Let's discuss this in detail:
1. Reproduction in water:
- Frogs lay their eggs in water, typically in ponds, streams, or other bodies of water.
- This process is called external fertilization, where the female frog releases a large number of eggs, and the male frog fertilizes them with sperm.
- The eggs are usually covered in a jelly-like substance to protect them from predators and provide a suitable environment for development.
- The eggs hatch into tadpoles, which are aquatic larvae with gills and a long tail.
2. Reproduction on trees:
- This option, B, is incorrect as frogs do not reproduce on trees. They may climb trees or plants for shelter or hunting, but their reproduction occurs in water.
3. Reproduction in sand:
- This option, C, is also incorrect as frogs do not reproduce in sand. They require water for their reproductive process.
4. Reproduction on lotus flowers in water:
- This option, D, is incorrect as well. While frogs may use lotus flowers or other plants for resting or hiding, their reproduction takes place in the water, not on the lotus flowers.
In conclusion, frogs reproduce by laying their eggs in water, and the correct answer is option A.