Q1. [1] § 13.1 ECO-SYSTEM — WHAT ARE ITS COMPONENTS?
Other than the abiotic components, which of the given biotic components are not required to make an aquarium with small herbivorous fishes a self-sustaining system ?
(i) Aquatic plants and aquatic animals
(ii) Terrestrial plants and terrestrial animals
(iii) Decomposers as bacteria and fungi
(iv) Consumers as clown fishes and sea urchins
- (A) (i) and (iv)
- (B) (ii) and (iii)
- (C) (i) and (iii)
- (D) (ii) and (iv)
Previously asked in CBSE board exam
2025 31/3/1 Q16
Generated by claude-sonnet-4-6 · 2026-06-15 06:42 · grounding rag
Model Answer
(D) (ii) and (iv)
Terrestrial plants/animals and consumers like clown fishes/sea urchins are not required. Aquatic plants (producers), herbivorous fishes (consumers), and decomposers (bacteria/fungi) make the aquarium self-sustaining.
Source: Chapter 13, Activity 13.1
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Explanation
The textbook states that adding aquatic plants and animals makes an aquarium a self-sustaining system. Decomposers (bacteria/fungi) break down dead matter — they are needed. Terrestrial organisms have no role in an aquatic system. Clown fishes and sea urchins are marine/carnivorous consumers not needed when herbivorous fish are already present as consumers. So (ii) terrestrial organisms and (iv) those specific consumers are not required → Option (D).
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