Structural Organisation in Animals Mock Test – Class 11 Biology

1. Use the heart arrangement described below. Chamber P and Chamber Q are thin-walled receiving chambers positioned above a single thicker pumping chamber R. The entire organ is enclosed by a membranous sac. Which identification is correct?

2. Order the events linking neural stimulation to skeletal movement.
P. The skeletal muscle fibres shorten.
Q. A disturbance travels along a neuron.
R. The attached bone moves at a joint.
S. Neuronal output stimulates the muscle.
T. Force is transmitted through the muscle attachment.

3. A microscopic section shows a single layer of very thin, flattened cells with irregular boundaries. The layer forms the wall separating air in a lung sac from nearby blood. It is:

4. The glandular and ciliated cells of the Malpighian tubules are severely damaged, but the hindgut remains open and muscular movement of the gut continues. The most direct consequence is:

5. Assess the following statements about neuronal output.
I. A suitable stimulus can initiate a disturbance in a neuron.
II. The disturbance travels along the neuronal plasma membrane.
III. Arrival at the endings must always stimulate the adjacent cell.
IV. A neuronal ending may stimulate or inhibit an adjacent neuron or another cell.

6. One circumpharyngeal branch connecting the ventral nerve cord with the cerebral ganglia is severed, while the opposite branch remains intact. Which conclusion is most defensible?

7. Assertion: A cockroach can possess a protective chitinous exoskeleton without making the entire body continuously rigid.
Reason: Hardened sclerites are joined to neighbouring plates by flexible arthrodial membranes.

8. A female cockroach produces between and oothecae, and each ootheca contains between and eggs. Assuming every ootheca has a value within these limits, what is the possible total range of eggs?

9. The medulla oblongata of a frog is severed where it passes through the foramen magnum and becomes continuous with the spinal cord. The most direct consequence is:

10. Rana tigrina is best identified as:

11. Equal intestinal segments receive the same concentration of completely digested nutrients. Segment P retains normal villi and microvilli, while Segment Q has an equally permeable but experimentally flattened lining. Nutrient uptake is lower in Q. The strongest conclusion is:

12. The strongest evidence that a group of organs forms an organ system is that the organs:

13. Set P contains organs connected by the passage of food and digestive secretions toward digestion and absorption. Set Q contains nearby body structures for which no shared activity or interaction is stated. From the supplied evidence:

14. Use the canal arrangement described below. Food passes from the oesophagus into a large storage chamber, then enters a thick-walled grinding organ before reaching the midgut. If label P marks the storage chamber and label Q marks the grinding organ, P and Q are:

15. Pair each cartilage-related feature with its description. Each Column II entry is used once.

16. Which symbolic set of pathways correctly shows circulation linking respiration and excretion in a frog?

17. Assertion: The cockroach gizzard is well suited for mechanical processing of food.
Reason: It possesses thick circular muscles and six chitinous teeth that can act on the stored food entering from the crop.

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

19. 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:

20. Sequence the stages in the normal route followed by a product from an exocrine gland.
P. The product reaches an epithelial surface or lumen.
Q. Secretory epithelial cells release the product.
R. The product enters the glandular duct.

21. Examine the statements below about the male cockroach reproductive pathway.
I. Testes produce sperm in abdominal segments .
II. Seminal vesicles store sperm.
III. The mushroom-shaped gland contributes to spermatophore formation.
IV. Phallomeres form part of the external genitalia.

22. The sinus venosus of a frog is correctly related to the heart as a structure that:

23. Let represent nephridia whose waste route enters the digestive tube and represent nephridia whose route opens directly outside. If denotes septal nephridia and denotes integumentary nephridia, the valid relation is:

24. 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:

25. Examine the records below.

The record requiring correction is:

26. 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.

27. Calciferous glands in the stomach stop secreting, but the gizzard remains fully functional. The expected pattern is:

28. A frog has normal hindlimb bones and muscles, but the webbing between its hind digits is greatly reduced. During swimming, the most direct effect is:

29. Assertion: Tendons and ligaments are examples of dense regular connective tissue.
Reason: Their compact collagen bundles run mainly in parallel and are suited to tension acting along a principal direction.

30. Relate each female reproductive structure or product with its principal relation. Each Column II entry is used once.

31. The pericardium surrounding the frog heart is best described as:

32. Equal earthworms are placed on the same moist rough surface. In treatment P, the setae are temporarily immobilised inside their pits without damaging the muscles; control worms retain normal setal movement. Treatment P shows strong body contractions but little forward progress. The strongest inference is:

33. Sequence the following events in one simplified cycle of setae-assisted earthworm locomotion.
P. Selected setae project and grip the soil.
Q. Muscular action displaces another part of the body relative to the anchored region.
R. The gripping setae retract.
S. A new region establishes anchorage for the next movement.

34. A female cockroach has two ovaries, each with ovarioles. In one ovary, ovarioles become non-functional; in the other, become non-functional. How many functional ovarioles remain altogether?

35. Examine the segmental records below.

The record requiring correction is:

36. Assertion: The amphibious life of a frog depends on coordinated action of several organ systems rather than on one isolated adaptation.
Reason: Moist skin supports exchange and water uptake, limbs support movement, blood transports gases and wastes, the cloaca receives products from several systems, and reproduction depends on water.

37. The tegmina of a cockroach are badly damaged, but the metathoracic hind wings remain intact and can unfold normally. The most likely immediate effect is:

38. Examine the statements below about earthworm cocoon development.
I. Mating involves exchange of spermatophores between two worms.
II. Gametes and nutritive fluid enter a cocoon associated with the clitellum.
III. Fertilisation and development occur inside the cocoon.
IV. A free-living larva emerges before becoming a young worm.

39. A mature earthworm has pairs of testes and pair of ovaries. One individual testis and one individual ovary become non-functional, while the remaining gonads are normal. What is the ratio of functional testes to functional ovaries?

40. The anterior chemoreceptors of an earthworm are damaged, while light-sensitive and touch-sensitive receptor cells remain functional. The most specific expected difficulty is:

41. Assertion: A frog can exchange respiratory gases through its skin while submerged in water.
Reason: Dissolved oxygen can diffuse across the moist, vascular skin.

42. Associate each respiratory structure of a cockroach with its principal relation. Each Column II entry is used once.

43. 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:

44. Let denote the number of cell layers in an epithelium. Sample P has and lines a narrow internal tube involved in exchange, while sample Q has and is repeatedly exposed to abrasion. The most suitable interpretation is:

45. 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:

46. A mature earthworm has segments, and its clitellum occupies segments . How many segments belong to the postclitellar region?

47. Examine the arrangement described below. A tissue from the heart contains striated cells that branch and join neighbouring cells through specialised junctions. The tissue is:

48. An adult frog has well-developed vocal sacs but one copulatory pad has been lost through injury. Which identification remains most defensible?

49. Examine the arrangement described below. A paired longitudinal cord lies below the alimentary canal and bears repeated ganglia. Near segments and , branches rise on both sides of the pharynx and join a dorsal pair of cerebral ganglia. The complete anterior arrangement forms:

50. 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: