Structural Organisation in Animals Mock Test – Class 11 Biology

1. Both mesorchia of a male frog are severed, but the testes, vasa efferentia, and blood supply remain intact. The most direct result is:

2. Assertion: Earthworm development normally includes a distinct free-living larval stage.
Reason: Young worms emerge from the cocoon without undergoing a larval transformation.

3. In a cockroach, the paired mandibles remain functional, but the median tongue-like mouthpart is immobilised. Which change is most likely?

4. A gland produces its secretion normally, but the product accumulates within the gland after a passage leading to an epithelial surface becomes obstructed. This gland is most consistently classified as:

5. Two cockroach groups have equally hardened tergites and sternites. In Group P, the arthrodial membranes remain flexible. In Group Q, those membranes are experimentally stiffened without damaging the plates. Group Q shows much less bending between adjacent body regions. The strongest inference is:

6. Assertion: Hermaphroditism in an earthworm does not eliminate the biological importance of mating with another worm.
Reason: Two worms exchange sperm-containing reproductive material, and received sperm can be stored for later use during cocoon reproduction.

7. Ganglia in several middle segments of an earthworm are selectively inactivated. Sensory input still reaches the anterior nervous region, but the affected segments no longer produce well-coordinated local responses. The strongest inference is:

8. Review the statements given below about mosaic vision in a cockroach.
I. Each compound eye contains numerous ommatidia.
II. The combined image is described as a mosaic.
III. Mosaic vision has high sensitivity but comparatively lower resolution.
IV. This visual organisation is unsuitable for a nocturnal animal.

9. Order the layers of the earthworm body wall from the external surface toward the coelom.
P. Circular muscle
Q. Cuticle
R. Coelomic epithelium
S. Epidermis
T. Longitudinal muscle

10. Place the events involved in a simple muscular response.
P. The muscle fibres shorten.
Q. A suitable stimulus acts on the muscle.
R. Movement or maintenance of position results.
S. The fibres relax after the response.

11. A harmless coating keeps an earthworm’s surface moist but is nearly impermeable to respiratory gases. The hearts continue beating and the blood glands remain functional. The most likely outcome is:

12. Evaluate the following statements about respiration in an earthworm.
I. Specialised respiratory organs are absent.
II. Gases diffuse through the moist body surface.
III. Oxygen entering through the surface can reach the bloodstream.
IV. Drying of the body surface improves gaseous diffusion.

13. The arrangement below is described in words. Region P consists of short branched processes approaching the cell body. Region Q is the cell body, Region R is one long process extending away from it, and Region S contains the terminal endings of that process. The usual direction of information flow is:

14. Examine the digestive records below.

The record requiring correction is:

15. The nephridial records are shown below.

The record requiring correction is:

16. Compare the two tissue samples shown below.

The most suitable identification is:

17. The mucus-secreting cells of a frog remain alive but suddenly stop releasing mucus. The surrounding air is dry, and the frog cannot enter water. The earliest expected change is:

18. Blood travelling from lower body regions toward the kidneys of a frog uses the:

19. Assertion: Dense irregular connective tissue is well suited to the skin.
Reason: Its collagen fibres run in varied orientations and can resist mechanical stress arriving from different directions.

20. A frog has normally muscular hindlimbs, but the webbing between its hind digits is greatly reduced and its skin has become nearly impermeable to gases. Its lungs remain intact. While submerged, the most likely combined effect is:

21. Which description correctly identifies the lungs of a frog?

22. An anterior view shows Structure P as a small lobe extending over the mouth, while Structure Q forms the first complete segment surrounding the mouth. The correct identification is:

23. Equal numbers of frogs are placed on matching and strongly contrasting backgrounds. Predators detect frogs less frequently when their colour resembles the background, while movement rate and predator number remain comparable. The result most strongly supports the conclusion that:

24. Household cockroaches can act as disease vectors most directly when they:

25. Smooth muscle in the wall of a blood vessel relaxes while the epithelial lining and connective support remain intact. Which immediate change is most likely?

26. Three transport-respiration profiles are shown.

Which mapping is correct?

27. In a neural-tissue sample, neuroglia occupy more than half of the tissue volume, while the neurons still respond to stimulation and conduct electrical disturbances. Which conclusion is most accurate?

28. A cockroach can ingest food normally, but three defects occur simultaneously: tracheolar gas exchange is reduced, Malpighian-tubule uptake is blocked, and several thoracic ganglia are inactive. Which combined outcome is most consistent?

29. The reproductive functions shown below are provisionally assigned.

The assignment requiring correction is:

30. The openings through which the cockroach vessels communicate with the haemocoelic sinuses become sealed, but the dorsal heart continues contracting. The most immediate system-level problem is:

31. Review the statements given below about blood and lymph in a frog.
I. Blood contains plasma, erythrocytes, leucocytes, and platelets.
II. Frog erythrocytes are nucleated and contain haemoglobin.
III. Lymph lacks erythrocytes and contains fewer proteins than blood.
IV. Lymph normally contains more erythrocytes and plasma proteins than blood.

32. The hepatic portal vessel connecting the intestine with the liver is blocked, while ordinary intestinal absorption continues. The most direct consequence is:

33. Sequence the pathway followed by oxygen from the environment to a cockroach body cell.
P. Oxygen enters a fine tracheole.
Q. Oxygen passes through a lateral spiracle.
R. Oxygen diffuses from the tracheole to the nearby cell.
S. Oxygen travels through a larger tracheal tube.

34. In a hollow organ, the compact epithelial lining is replaced by loose areolar tissue, while the smooth-muscle layer remains functional. The most likely early pattern is:

35. Examine the statements below.
I. Fibres in connective tissue are extracellular matrix components, whereas a muscle fibre is a contractile cellular structure.
II. A large amount of intercellular matrix is essential for an effective epithelial barrier.
III. Neuroglia support and protect, while neurons provide the primary excitable pathway.
IV. An organ may combine epithelial, connective, muscular, and neural tissues in a characteristic arrangement.

36. Associate each location with the epithelial type that best suits its stated role. Column II entries may be reused.

37. Assess the following statements about the male reproductive system of a cockroach.
I. Paired testes lie laterally in abdominal segments .
II. Each testis connects with a vas deferens.
III. Sperm may be stored in seminal vesicles.
IV. The ejaculatory duct opens at a male gonopore ventral to the anus.

38. A mutation selectively prevents tight junctions from forming, while adhering and gap junctions remain functional. The most direct epithelial defect would be:

39. A person voluntarily bends the forearm. The relevant skeletal muscle shortens normally, but its attachment to the forearm bone is completely severed. The most likely outcome is:

40. When the same frog is kept first in a cool environment and then under otherwise similar warm conditions, its body temperature is lower in the cool setting. This observation most directly demonstrates:

41. Assertion: A female frog can retain normal urine conduction even when both oviducts are obstructed.
Reason: Female ureters and oviducts are separate ducts that open independently into the cloaca.

42. Use the external arrangement described below. Region P contains the mouth, nostrils, eyes, and tympana. Region Q extends posteriorly and bears both pairs of limbs. No narrow movable region separates P from Q, and no tail projects behind Q. The correct interpretation is:

43. Examine the locations and proposed epithelial roles below.

Which row contains the incompatible combination?

44. Evaluate the following statements about the earthworm alimentary canal.
I. It forms a straight passage from mouth to anus.
II. The pharynx lies in segment .
III. The stomach occupies segments .
IV. The intestine begins at segment .

45. The consequences of selectively impairing epithelial junctions are recorded below.

The most appropriate junctional assignments are:

46. An earthworm is transferred from moist soil to a dry surface while air remains available. If water loss from the skin is not prevented, the most likely early consequence is:

47. Samples of adipose tissue are examined before and after a prolonged nutrient surplus. After the surplus, individual adipocytes contain visibly larger fat deposits, while no measurement of cell number is made. The evidence supports the conclusion that:

48. In a heart, the epithelial lining, connective support, and neural input remain intact, but the muscular tissue can no longer shorten. The most defensible prediction is:

49. A tubule is lined by one layer of cells that are nearly as tall as they are wide. Their nuclei appear rounded and approximately central, and no multiple protective layers are present. The lining is:

50. Place the following regions from the anterior end toward the posterior end of a mature earthworm.
P. Clitellar region
Q. Postclitellar region
R. Preclitellar region