Structural Organisation in Animals — Class 11 MCQs with Answers

Structural Organisation in Animals — important questions & MCQs with answers (Class 11 Biology)

6 solved questions from this chapter's difficulty levels, each with its answer and explanation. Tap an option to check yourself.

0 of 6 answered

1. Q1 of 6Easy

   Tissue lining the body cavities:

   AEpithelialBMuscleCNervousDConnective
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   Answer: Epithelial

   Explanation: Epithelial tissue lines cavities and covers surfaces, sitting on a basement membrane with almost no matrix — connective tissue looks similar but is packed with matrix between its cells instead.

2. Q2 of 6Easy

   A group of similar cells with common origin performing a specific function is called?

   ATissueBOrganCOrgan systemDOrganism
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   Answer: Tissue

   Explanation: A tissue is a group of similar cells with a common origin that work together to perform one specific function — the next level up, an organ, instead combines several different tissue types.

3. Q3 of 6Medium

   Earthworm respires through:

   AGillsBLungsCMoist skinDTracheae
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   Answer: Moist skin

   Explanation: Earthworms have no lungs, gills or tracheae; oxygen diffuses directly across their thin, moist, vascular skin — cutaneous respiration, unlike the tracheal system insects such as cockroaches use.

4. Q4 of 6Medium

   Blood is a:

   AEpithelial tissueBFluid connective tissueCMuscleDNervous
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   Answer: Fluid connective tissue

   Explanation: Blood counts as connective tissue because its cells (RBCs, WBCs, platelets) sit in a non-living matrix — here liquid plasma, instead of the solid matrix of bone or cartilage the name usually suggests.

5. Q5 of 6Hard

   Assertion: Earthworms are detritivores. Reason: They feed on decaying organic matter and enrich soil.

   AA true, R falseBBoth true; R doesn't explain ACBoth true; R explains ADA false, R true
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   Answer: Both true; R explains A

   Explanation: Earthworms are detritivores that ingest decaying leaves and organic matter as they burrow, aerating and enriching the soil in the process — this feeding habit is exactly why they're called farmers' friends.

6. Q6 of 6Hard

   Frog's heart has ___ chambers.

   A4B3C2D1
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   Answer: 3

   Explanation: A frog's heart has three chambers — two atria and one ventricle — unlike the four-chambered mammalian heart; the single shared ventricle is why oxygenated and deoxygenated blood partially mix.

Structural Organisation in Animals notes: key concepts (Class 11 Biology)

Beyond single cells, animal bodies are organised into tissues, organs and systems. Four tissue types — epithelial, connective, muscular and nervous — build every organ, while the earthworm, cockroach and frog serve as model organisms whose morphology and anatomy reveal how these tissues assemble into working systems.

Epithelial tissue

A compact sheet of cells on a basement membrane, with little matrix; classified by cell shape as squamous, cuboidal or columnar, it lines and protects surfaces.

Simple vs compound epithelium

Simple epithelium is one cell thick for absorption and secretion; compound (stratified) epithelium is many-layered, protecting skin and the buccal cavity.

Cell junctions

Tight junctions seal cells to stop leakage, adhering junctions cement neighbours, and gap junctions allow direct cytoplasmic exchange of small molecules.

Connective tissue

Cells lie scattered in an abundant matrix; it includes loose (areolar, adipose), dense (tendons, ligaments), and specialised cartilage, bone and blood.

Blood as connective tissue

A fluid connective tissue with a plasma matrix carrying RBCs, WBCs and platelets; it transports gases, nutrients, hormones and wastes around the body.

Muscular tissue

Elongated contractile fibres: skeletal (striated, voluntary), smooth (unstriated, involuntary, in visceral organs) and cardiac (striated, involuntary, heart).

Neural tissue

Neurons that sense stimuli and conduct impulses, supported by neuroglia; the neuron responds rapidly to change and transmits electrical signals over distance.

Earthworm morphology

Pheretima has a segmented (metameric) body with setae for movement and a glandular clitellum for cocoon formation; it is a burrowing hermaphrodite detritivore.

Earthworm digestion

A straight tube from mouth to anus with pharynx, a gizzard that grinds soil, and an intestine bearing a typhlosole that boosts absorptive surface area.

Cockroach morphology

Periplaneta has head, thorax and abdomen, a chitinous exoskeleton, three pairs of legs and two pairs of wings; it is a nocturnal omnivore with separate sexes.

Cockroach systems

Open circulation with haemolymph, respiration through tracheae opening at spiracles, and excretion via Malpighian tubules; blood does not carry oxygen.

Frog morphology

Rana tigrina is a moist-skinned amphibian showing camouflage, with webbed hind limbs for swimming; it respires through skin, buccal cavity and lungs.

Frog anatomy

Closed double circulation with a three-chambered heart, digestive glands (liver, pancreas), kidneys for excretion, and separate sexes with external fertilisation in water.