Morphology and Anatomy of Animals MCQ Quiz - Objective Question with Answer for Morphology and Anatomy of Animals - Download Free PDF

The correct answer is Skin

Explanation:

Frogs are amphibians, meaning they can live both in water and on land. They have developed various methods for respiration to adapt to their environments.

• During hibernation (a state of inactivity during winter) and aestivation (a state of inactivity during summer), frogs undergo metabolic depression to survive in extreme conditions.
• Frogs respire on land and in the water by two different methods.
• In water, skin acts as aquatic respiratory organ (cutaneous respiration). Dissolved oxygen in the water is exchanged through the skin by diffusion.
• On land, the buccal cavity, skin and lungs act as the respiratory organs.
• The respiration by lungs is called pulmonary respiration. The lungs are a pair of elongated, pink coloured sac-like structures present in the upper part of the trunk region (thorax).
• Air enters through the nostrils into the buccal cavity and then to lungs.
• During aestivation and hibernation gaseous exchange takes place through skin.

Other Options:

• Buccal Cavity: The buccal cavity is involved in a process called buccal pumping, where frogs can take in air through their mouths and into their lungs. 
• Lungs and Buccal Cavity: While frogs do use their lungs and buccal cavity for respiration when they are active, these organs are not as effective during periods of inactivity like hibernation and aestivation because the metabolic rate is significantly reduced.
• Lungs: Frogs use their lungs primarily for respiration when they are active on land. 

The correct answer is Mimicry

Explanation:

• Frogs have the ability to change the colour to hide them from their enemies (camouflage).
• This protective coloration is called mimicry. 
• ​Frogs take shelter in deep burrows to protect them from extreme heat and cold.
• This is known as summer sleep (aestivation) and winter sleep (hibernation) respectively.

The correct answer is To join the right atrium and receive blood from the vena cava

Explanation:

• Heart is a muscular structure situated in the upper part of the body cavity.
• The frog's heart consists of three chambers: two atria and one ventricle and is covered by a membrane called pericardium.
• A triangular structure called sinus venosus joins the right atrium. It receives blood through the major veins called vena cava.
• The sinus venosus is a thin-walled sac that collects deoxygenated blood from the veins before passing it to the right atrium. It plays a crucial role in the circulation of deoxygenated blood, ensuring it is directed to the heart for oxygenation.
• The sinus venosus eventually merges with the right atrium, facilitating the flow of blood into the heart's atrial chambers.

• The ventricle opens into a sac- like conus arteriosus on the ventral side of the heart. The blood from the heart is carried to all parts of the body by the arteries (arterial system).

Other Options

• To pump blood to the body: This is the function of the ventricles, not the sinus venosus.
• To oxygenate the blood: Oxygenation of blood occurs in the lungs and skin in frogs, not in the sinus venosus.
• To filter the blood: Blood filtration is primarily a function of the kidneys, not the sinus venosus.

The correct answer is On the ventral side of the heart

Concept:

• The frog's heart is structured in such a way that it contains three chambers: two atria and one ventricle.
• The conus arteriosus is a muscular tube that serves as a passage for blood, moving it from the ventricle to the rest of the body.
• Located on the ventral (front) side of the heart, it plays a significant role in managing the flow of blood from the heart to the arteries.
• This structure helps in maintaining a controlled and directed flow of blood, preventing any backflow into the ventricle.

Additional Information

• The vascular system of frog is well-developed closed type.
• Heart is a muscular structure situated in the upper part of the body cavity. It has three chambers, two atria and one ventricle and is covered by a membrane called pericardium.
• A triangular structure called sinus venosus joins the right atrium. It receives blood through the major veins called vena cava.
• The ventricle opens into a sac- like conus arteriosus on the ventral side of the heart. The blood from the heart is carried to all parts of the body by the arteries (arterial system).

The correct answer is Only 1 and 3 are correct

Explanation:

• In male frogs, the testes produce sperm, which is transported via the vasa efferentia to the kidneys, and then to the ureters which opens into the cloaca.
• In female frogs, ovaries are located near the kidneys and during reproduction, eggs pass from the ovaries into the coelomic cavity and then into the oviducts which are not functionally connected to the kidneys.
• The cloaca in frogs serves as a common chamber and passageway for the intestinal, urinary, and genital tracts, making it a shared chamber for excretion, digestive wastes, and reproductive cells.

According to NCERT:

• Frogs have well organised male and female reproductive systems.
• Male reproductive organs consist of a pair of yellowish ovoid testes which are found adhered to the upper part of kidneys by a double fold of peritoneum called mesorchium.
  • Vasa efferentia are 10-12 in number that arise from testes. They enter the kidneys on their side and open into Bidder’s canal. Finally it communicates with the urinogenital duct that comes out of the kidneys and opens into the cloaca.
  • The cloaca is a small, median chamber that is used to pass faecal matter, urine and sperms to the exterior.
• The female reproductive organs include a pair of ovaries.
  • The ovaries are situated near kidneys and there is no functional connection with kidneys.
  • A pair of oviduct arising from the ovaries opens into the cloaca separately.

Concept:

• Earthworms belong to the phylum Annelida of the kingdom Animalia.
• These are terrestrial, bilaterally symmetrical, and exhibit organ system level of body organization.
• The body surface of the earthworms is distinctly marked out in segments or metameres.
• They have a long cylindrical body divided into about 100-120 metameres.
• The dorsal surface of the earthworm's body is marked by a dark median mid-dorsal line along the longitudinal axis of the body.
• The presence of genital pores distinguishes the ventral surface of earthworms.
• The earthworm's body is divisible into three prominent regions - preclitellar, clitellar, and postclitellar segments.
• The first body segment of an earthworm is called the peristomium, i.e. buccal segment.

Important Points

• A pair of short and conical intestinal caecae projects from the intestine on the 26th segment.
• The characteristic feature of the intestine is the presence of typhlosole.
• Typhlosole is the internal median fold of the intestinal wall that runs along most of its length.
• Typhlosole lies between 26-35 segments.
• It increases the effective area of absorption in the intestine. 

Additional Information

• The buccal cavity lies in the 1-3 segments of earthworms, which leads into the muscular pharynx.
• The oesophagus lies in the 5-7 segments.
• The stomach of the earthworm extends from 9-14 segments.

Hence, the correct option is (4) 26-35 segments.

Key Points

• Frogs belong to the class Amphibia or phylum Chordata.
• They show sexual dimorphism.
• Male and female frogs have distinguishing morphological features:
  • Male frogs show the presence of sound-producing vocal sacs that are absent in female frogs.
  • Male frogs also show a copulatory pad on the first digit of the forelimbs which is absent in female frogs.

Explanation:

• The male frogs produce the croaking sound during their breeding season in order to attract females for mating.
• The croaking sound also demarcates a male territory.
• The larynx or voice sac is either absent or rudimentary in female frogs.
• Therefore, females do not produce the croaking sound.

The correct answer is Only 1 and 3 are correct

Explanation:

• In male frogs, the testes produce sperm, which is transported via the vasa efferentia to the kidneys, and then to the ureters which opens into the cloaca.
• In female frogs, ovaries are located near the kidneys and during reproduction, eggs pass from the ovaries into the coelomic cavity and then into the oviducts which are not functionally connected to the kidneys.
• The cloaca in frogs serves as a common chamber and passageway for the intestinal, urinary, and genital tracts, making it a shared chamber for excretion, digestive wastes, and reproductive cells.

According to NCERT:

• Frogs have well organised male and female reproductive systems.
• Male reproductive organs consist of a pair of yellowish ovoid testes which are found adhered to the upper part of kidneys by a double fold of peritoneum called mesorchium.
  • Vasa efferentia are 10-12 in number that arise from testes. They enter the kidneys on their side and open into Bidder’s canal. Finally it communicates with the urinogenital duct that comes out of the kidneys and opens into the cloaca.
  • The cloaca is a small, median chamber that is used to pass faecal matter, urine and sperms to the exterior.
• The female reproductive organs include a pair of ovaries.
  • The ovaries are situated near kidneys and there is no functional connection with kidneys.
  • A pair of oviduct arising from the ovaries opens into the cloaca separately.

The correct answer is Only Statement 1 is correct

Explanation:

• Frogs have well organised male and female reproductive systems.
• Male reproductive organs consist of a pair of yellowish ovoid testes which are found adhered to the upper part of kidneys by a double fold of peritoneum called mesorchium.
  • Vasa efferentia are 10-12 in number that arise from testes. They enter the kidneys on their side and open into Bidder’s canal. Finally it communicates with the urinogenital duct that comes out of the kidneys and opens into the cloaca.
  • The cloaca is a small, median chamber that is used to pass faecal matter, urine and sperms to the exterior.

Fig: Male reproductive organ                                              Fig: Female reproductive organ

• The female reproductive organs include a pair of ovaries.
  • The ovaries are situated near kidneys and there is no functional connection with kidneys.
  • A pair of oviduct arising from the ovaries opens into the cloaca separately.

The correct answer is On the ventral side of the heart

Concept:

• The frog's heart is structured in such a way that it contains three chambers: two atria and one ventricle.
• The conus arteriosus is a muscular tube that serves as a passage for blood, moving it from the ventricle to the rest of the body.
• Located on the ventral (front) side of the heart, it plays a significant role in managing the flow of blood from the heart to the arteries.
• This structure helps in maintaining a controlled and directed flow of blood, preventing any backflow into the ventricle.

Additional Information

• The vascular system of frog is well-developed closed type.
• Heart is a muscular structure situated in the upper part of the body cavity. It has three chambers, two atria and one ventricle and is covered by a membrane called pericardium.
• A triangular structure called sinus venosus joins the right atrium. It receives blood through the major veins called vena cava.
• The ventricle opens into a sac- like conus arteriosus on the ventral side of the heart. The blood from the heart is carried to all parts of the body by the arteries (arterial system).

The correct answer is Only Statement I is correct.

Concept:

• Frogs have the ability to change the colour to hide them from their enemies (camouflage). This protective coloration is called mimicry. Frogs can change their color. They show different color in grasses and on dry land. 
• Frogs are not seen during peak summer and winter. During this period they take shelter in deep burrows to protect them from extreme heat and cold. This is known as summer sleep (aestivation) and winter sleep (hibernation) respectively.

Explanation:

• Statement I: This statement is correct. Frogs have the ability to change their color to blend into their environments, a phenomenon known as camouflage, which helps them hide from predators.
• Statement II: This statement is incorrect. Frogs undergo hibernation in the winter, but the term for summer dormancy is aestivation, not hibernation. Therefore, the statement confuses the terms for winter sleep and summer sleep.

The correct answer is Peristomium

Explanation:-

• The earthworm is a reddish-brown terrestrial invertebrate.23
• The common Indian earthworms are Pheretima and Lumbricus.
• They inhabit the upper layer of the moist soil.
• During day time, they live in burrows made by boring and swallowing the soil.

Key Points

• Earthworms have a long cylindrical body. The body is divided into more than a hundred short segments which are similar (metameres about 100-120 in number)
• The first body segment is called the Peristomium (buccal segment) which contains the mouth
• The mouth present in the peristomium is covered by a lobe called the prostomium, it serves as a covering for the mouth and as a wedge to force open cracks in the soil into which the earthworm may crawl. The prostomium is sensory in function
• In a mature worm, segments 14-16 are covered by a prominent dark band of glandular tissue called clitellum. This divides the body into three prominent regions – preclitellar, clitellar and postclitellar segments
• In each body segment, except the first, last and clitellum, there are rows of S-shaped setae, embedded in the epidermal pits in the middle of each segment.
• Setae can be extended or retracted, their principal role is in locomotion
• 

Conclusion:- Peristomium is the first body segment of earthworm.

The correct answer is External Fertilization.

Key Points

• External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body.
• External fertilization occurs when both eggs and sperm are released into the water. 
• After the sperm reaches the egg, fertilization takes place. 
• Each sperm swim randomly in water with help of its long tail. The sperm comes in contact with eggs.
• This type of fertilization in which the fusion of a male and a female gamete takes place outside the body of the female is called external fertilization.
• The release of the reproductive material may be triggered by water temperature or the length of daylight.

The correct answer is Only 1 and 3 are correct

Concept:

• The system for control and coordination is highly evolved in the frog.
• The nervous system is organised into a central nervous system (brain and spinal cord), a peripheral nervous system (cranial and spinal nerves) and an autonomic nervous system (sympathetic and parasympathetic).
• There are ten pairs of cranial nerves arising from the brain.
• Brain is enclosed in a bony structure called brain box (cranium).
• The brain is divided into fore-brain, mid-brain and hind-brain.
• Forebrain includes olfactory lobes, paired cerebral hemispheres and unpaired diencephalon. The midbrain is characterised by a pair of optic lobes. Hind-brain consists of cerebellum and medulla oblongata.
• The medulla oblongata passes out through the foramen magnum and continues into spinal cord, which is enclosed in the vertebral column.
• External ear is absent in frogs and only tympanum can be seen externally. The ear is an organ of hearing as well as balancing (equilibrium).

Explanation:

• The brain of a frog is divided into forebrain, midbrain, and hindbrain: This statement is correct. The frog’s brain is composed of these three major parts, each with specific functions.
• Frogs have external ears that help in hearing and balancing: This statement is incorrect. Frogs do not have external ears like humans; instead, they have a tympanic membrane (eardrum) which functions in hearing. Balance is maintained by the inner ear structures.
• The cerebellum is part of the frog's hindbrain: This statement is correct. The cerebellum is indeed a part of the hindbrain and is involved in coordinating movement and balance.

The correct answer is Ciliated

Explanation:

• Squamous epithelium: This type of epithelium is found in the endothelium of blood vessels. It consists of flat cells that allow for easy exchange of substances.
• Cuboidal epithelium: This type of epithelium is found in nephrons. It consists of cube-shaped cells that are involved in secretion and absorption.
• Columnar epithelium: This type of epithelium lines the stomach. It consists of tall, column-like cells that are specialized for absorption and secretion.
• Ciliated epithelium: Ciliated epithelial tissue is found in the fallopian tube, which helps in the movement of the ovum. This type of epithelium is mainly present in the inner surface of hollow organs like bronchioles and fallopian tubes. The cilia help in moving mucus and other substances out of the respiratory tract.