Consider the following statements regarding the vascular and lymphatic systems of frogs:
I. The lymphatic system consists of lymph, lymph channels, and lymph nodes, and lymph lacks RBCs and a few proteins compared to blood. II. The heart is a muscular structure with three chambers: one atrium and two ventricles, covered by a pericardial membrane. III. A triangular structure called sinus venosus joins the right atrium and receives blood through the major veins called vena cava. IV. The renal portal system is a special venous connection between the liver and the intestine.
Explanation: Statement I is correct because the lymphatic system consists of lymph, lymph channels and lymph nodes, and lymph lacks RBCs and a few proteins compared to blood. Statement II is incorrect because the frog heart has two atria and one ventricle, not one atrium and two ventricles. Statement III is correct because the sinus venosus is a triangular chamber that joins the right atrium and receives blood through the vena cava. Statement IV is incorrect because the hepatic portal system connects the liver and intestine, whereas the renal portal system connects the kidneys with the posterior parts of the body.
Question 2 of 101
📘 CLASS XI
Consider the following statements regarding cellular organization in multicellular and unicellular organisms:
I. In unicellular organisms, all vital functions like digestion, respiration, and reproduction are performed by a single cell. II. The body of a simple organism like Hydra is composed of only one type of cell. III. In multicellular animals, a group of similar cells along with intercellular substances perform a specific function, constituting a tissue. IV. All complex animals are made of hundreds of basic types of tissues.
Explanation: Statement I is correct because unicellular organisms perform all life processes within a single cell. Statement II is incorrect because Hydra possesses several different types of cells. Statement III is correct because a tissue consists of similar cells together with intercellular substances performing a specific function. Statement IV is incorrect because all complex animals possess only four basic tissue types.
Question 3 of 101
📘 CLASS XI
Consider the following statements regarding the hierarchy of organ and organ systems:
I. Organs are organized in specific proportions and patterns to form basic tissues. II. When two or more organs perform a common function by their physical and/or chemical interaction, they together form an organ system. III. Cells, tissues, organs, and organ systems split up the work in a way that exhibits division of labour. IV. An organization of organs and organ systems is essential for more efficient and better-coordinated activities of millions of cells in multicellular organisms.
Explanation: Statement I is incorrect because tissues organize to form organs. Statements II, III and IV are correct because interacting organs form organ systems, which demonstrate division of labour and ensure efficient coordination of body functions.
Question 4 of 101
📘 CLASS XI
Analyze the following statements regarding tissue composition of organs and biological terms:
I. Each organ in a multicellular organism is strictly made of only one type of tissue. II. The vertebrate heart consists of all four basic types of tissues: epithelial, connective, muscular, and neural. III. Complexity in organ and organ systems displays a random pattern with no discernable evolutionary trend. IV. The word anatomy conventionally refers to the study of the morphology of internal organs in animals.
Explanation: Statement I is incorrect because organs are composed of one or more tissue types. Statement II is correct because the vertebrate heart contains epithelial, connective, muscular and neural tissues. Statement III is incorrect because organ-system complexity follows a discernible evolutionary trend. Statement IV is correct because anatomy conventionally refers to the study of internal organ morphology.
Question 5 of 101
📘 CLASS XI
Consider the following statements regarding the general characteristics of frogs:
I. Frogs can live both on land and in freshwater and belong to class Amphibia of phylum Chordata. II. Rana tigrina is the most common species of frog found in India. III. Frogs maintain a constant body temperature that does not change with the environment. IV. The ability to change skin colour to hide from enemies is called camouflage, and this protective coloration is termed mimicry.
Explanation: Statements I, II and IV are correct. Frogs are amphibians, Rana tigrina is the common Indian bullfrog, and camouflage helps in protection. Statement III is incorrect because frogs are cold-blooded (poikilothermic) and their body temperature varies with the environment.
Question 6 of 101
📘 CLASS XI
Consider the following statements regarding dormancy and seasonal adaptation in frogs:
I. During peak summer and winter, frogs take shelter in deep burrows to protect themselves from extreme temperatures. II. Summer sleep of frogs is known as hibernation, whereas winter sleep is known as aestivation. III. Frogs continue to feed actively and reproduce during their stay in deep burrows. IV. Respiration during summer sleep and winter sleep takes place through the skin.
Explanation: Statement I is correct because frogs hide in deep burrows during extreme seasons. Statement II is incorrect because summer sleep is aestivation and winter sleep is hibernation. Statement III is incorrect because frogs remain dormant. Statement IV is correct because gaseous exchange occurs through the skin during aestivation and hibernation.
Question 7 of 101
📘 CLASS XI
Consider the following statements about the skin of the frog:
I. The skin is smooth and slippery due to the presence of mucus, which always maintains it in a moist condition. II. The colour of the dorsal side of the body is uniformly pale yellow, while the ventral side is olive green with dark spots. III. The frog never drinks water but instead absorbs it through its skin. IV. Skin of the frog is highly vascularized and acts as a respiratory organ on land and in water.
Explanation: Statement I is correct because mucus glands keep the skin smooth, slippery and moist. Statement II is incorrect because the dorsal side is olive green with dark irregular spots, while the ventral side is uniformly pale yellow. Statement III is correct because frogs absorb water through their skin instead of drinking it. Statement IV is correct because the highly vascular skin functions as an important respiratory organ both on land and in water.
Question 8 of 101
📘 CLASS XI
Consider the following statements regarding the external features of a frog's head and trunk:
I. The body of a frog is divided into head, neck, trunk, and tail. II. A pair of nostrils is present above the mouth. III. Eyes are bulged and covered by a nictitating membrane that protects them while in water. IV. A membranous tympanum (ear) on either side of the eyes receives sound signals.
Explanation: Statement I is incorrect because the frog's body is divisible only into head and trunk; neck and tail are absent. Statements II, III and IV are correct because nostrils are present above the mouth, the eyes are protected by a nictitating membrane, and the tympanum receives sound vibrations.
Question 9 of 101
📘 CLASS XI
Analyze the following statements regarding the limbs and sexual dimorphism in frogs:
I. The forelimbs of a frog end in five digits and are larger and more muscular than the hind limbs. II. Hind limbs end in five digits, and the feet have webbed digits that help in swimming. III. Male frogs can be distinguished by the presence of sound-producing vocal sacs. IV. Female frogs possess a copulatory pad on the first digit of the forelimbs, which is absent in males.
Explanation: Statement I is incorrect because the forelimbs have four digits, whereas the larger hind limbs have five digits. Statements II and III are correct because webbed hind limbs aid swimming and vocal sacs are present in male frogs. Statement IV is incorrect because the copulatory pad is a feature of male frogs.
Question 10 of 101
📘 CLASS XI
Consider the following statements regarding the layout of the digestive tract in frogs:
I. The alimentary canal is short because frogs are carnivores, resulting in a reduced length of the intestine. II. The mouth opens into the buccal cavity, which leads to a short oesophagus through the pharynx. III. The stomach continues as the intestine, rectum, and finally opens outside by the cloaca. IV. The primary digestive glands are the liver, which secretes bile, and the pancreas, which produces pancreatic juice.
Explanation: All four statements are correct. Frogs possess a comparatively short alimentary canal because of their carnivorous habit. The alimentary canal extends from mouth to cloaca through the buccal cavity, pharynx, oesophagus, stomach, intestine and rectum. The liver secretes bile and the pancreas produces pancreatic juice.
