Structural Organisation in Animals Mock Test – Class 11 Biology

1. Gizzard contraction is selectively prevented in an earthworm, while calciferous-gland secretion remains normal. Compared with an unaffected worm, the treated animal is expected to show:

2. An earthworm remains on a drying surface. Its hearts continue contracting and its setae still grip the substrate, but the skin progressively loses moisture. The most likely sequence leading to reduced locomotor activity is:

3. The thoracic appendage records below are examined.

Which record must be corrected?

4. Order the structures in the pathway followed by sperm from its site of production to the male gonopore.
P. Ejaculatory duct
Q. Testis
R. Seminal vesicle
S. Vas deferens

5. Examine the segmental records below.

The record requiring correction is:

6. Gametes enter an earthworm cocoon normally, but the nutritive fluid is absent. Fertilisation may still begin, yet development is most likely to:

7. The widths and positions of four canal regions are recorded below.

Which region has an incompatible observation?

8. In a controlled comparison, a cockroach with reduced heart pumping but intact spiracles and tracheoles maintains tissue oxygen for a short period. A frog with normally ventilated lungs but a comparable reduction in blood flow shows a marked fall in tissue oxygen delivery. Which inference best fits the observations?

9. 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.

10. Both external nostrils of a frog are completely blocked, while the skin and lungs remain structurally normal. During active life on land, the most direct effect is:

11. A striated muscle sample contracts without voluntary control. The location label has been lost, so striation and control alone do not establish whether it is cardiac or skeletal. The additional observation that settles the identification is:

12. Frog eggs hatch normally, but the resulting tadpoles remain alive without acquiring the adult body form. Which process has failed most directly?

13. The ovaries of a female frog are experimentally shifted farther away from the kidneys without damaging their blood supply or the continuous oviducts. Which outcome is most consistent with the normal anatomy?

14. Assess the following statements about the ecological and human significance of frogs.
I. Frogs consume insects and may help protect crops.
II. Frogs participate in food chains and food webs.
III. Frog legs are consumed as food in some countries.
IV. Every frog species is harvested as food in all countries.

15. Let and denote the segments bearing the female genital pore and male genital pores, respectively. The valid positional relation is:

16. Review the statements given below about bone tissue.
I. Its matrix contains calcium salts and collagen fibres.
II. Osteocytes occupy lacunae within the matrix.
III. Its matrix is normally as pliable as that of cartilage.
IV. Its hardness contributes to support and protection.

17. Pair each epithelial junction with its principal role. Each Column II entry is used once.

18. Assess the following statements about cockroach development.
I. The nymph resembles a small adult in general body form.
II. The nymph lacks functional wings and mature reproductive organs.
III. A distinct pupal stage occurs between the nymph and adult.
IV. The nymph moults repeatedly before becoming an adult.

19. The microvilli of intestinal columnar epithelial cells are lost, but the cells remain arranged as an intact single layer. The most likely initial effect is:

20. Which sequence places the listed earthworm reproductive landmarks from anterior to posterior?
P. Spermathecae in segments
Q. Testes in segments and
R. Ovaries near the septum between segments and
S. Female pore on segment
T. Male pores on segment

21. Use the cross-sectional arrangement described below. Region P is a thin acellular covering. Region Q is a single columnar layer with secretory cells. Region R is the outer muscle layer, Region S is the deeper muscle layer, and Region T faces the coelom. Regions R and S are, respectively:

22. An earthworm is described as hermaphroditic. This classification means that one mature individual:

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

24. A dissected brain region contains olfactory lobes, two cerebral hemispheres, and a single diencephalon. The region is the:

25. Suppose a tendon is rebuilt with collagen fibres running in many directions, while a region of skin is rebuilt with mainly parallel collagen bundles. Which outcome is most likely?

26. 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?

27. Earthworms are placed in a chamber containing equal moisture on both sides. One side is illuminated, while the other remains dark. Control worms move preferentially toward the darker side, but worms with disabled light-sensitive receptor cells show no consistent preference. The result supports the conclusion that:

28. After pesticide contamination of a wetland, frog numbers fall, crop-feeding insects become more abundant nearby, and a predator that regularly consumes frogs also declines. Which interpretation best accounts for the combined observations?

29. Review the statements given below about the cockroach head.
I. It represents the fusion of six segments.
II. It is triangular and lies approximately at right angles to the body axis.
III. A flexible neck permits movement in several directions.
IV. Its mobility depends on the six segments remaining externally separate.

30. Assertion: Endocrine glands are described as ductless glands.
Reason: Their hormones are released into the fluid bathing the gland rather than being carried through a glandular duct.

31. The boat-shaped seventh sternum of a female cockroach develops as a flat plate, while the eighth and ninth sterna and reproductive openings remain present. The most direct consequence is:

32. Place the structures in the route followed by sperm from a frog testis toward the exterior.
P. Bidder's canal
Q. Cloaca
R. Vasa efferentia
S. Urinogenital duct
T. Testis

33. Compare the crop and gizzard of a cockroach.

Which conclusion is best supported?

34. A flexible connective tissue retains its collagen fibres but loses most of its elastin. When stretched within a safe range, it would most probably:

35. A temporary pond contains newly fertilised frog eggs, but it dries completely before the larvae can develop. Which outcome is most likely?

36. Examine the circulatory records below.

The record requiring correction is:

37. A specimen retains internal segmental organisation, but its shallow external grooves become difficult to see after the body surface swells. Which conclusion is most defensible?

38. Relate each earthworm-related activity with its principal ecological or practical outcome. Each Column II entry is used once.

39. Assertion: The prostomium assists an earthworm during burrowing.
Reason: It projects near the mouth and acts as a wedge against the soil.

40. A treatment selectively removes much of the calcium salts from a long bone while leaving most collagen fibres and osteocytes intact. The treated bone becomes less rigid but does not immediately lose every form of tensile strength. This observation is best explained by:

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

42. Suppose the cells of an epithelial covering become widely separated by abundant intercellular material while the exposed surface remains under mechanical stress. The most immediate functional consequence would be:

43. Phallomeres in a male cockroach are:

44. An earthworm is injured across segments . The damage includes part of the blood-gland region but leaves segment of the gizzard intact. Which combined effect is most likely?

45. Use the orientation described below. Structure P is a compact triangular capsule containing fused segments. Its broad surface faces forward and downward, while a narrow flexible connection joins it to the next body region. Structure P is:

46. Evaluate the following statements about the thorax of a cockroach.
I. It is divided into prothorax, mesothorax, and metathorax.
II. Each thoracic segment bears one pair of walking legs.
III. The short neck connecting the head with the thorax is an extension of the prothorax.
IV. All three pairs of walking legs arise from the mesothorax.

47. A female cockroach specimen has paired ovaries extending through abdominal segments . Each ovary leads into a lateral oviduct, and the two oviducts join a median vagina. This arrangement most directly supports:

48. Assertion: Cockroach development is described as paurometabolous.
Reason: The young stage resembles a small wingless adult and becomes adult through successive moults without a pupal stage.

49. Which sequence correctly represents the passage of food through the frog alimentary canal?

50. Two groups of cockroaches have intact tegmina. In Group P, the membranous hind wings are selectively removed; Group Q remains untreated. P can still cover the dorsal thorax with its forewings but shows a major decline in flight. The strongest inference is: