SSC CGL 2024 Tier-I · 9 September 2024, Shift 2 · General Awareness · Question 3 of 100

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 5 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

Which of the following can be represented as a functional unit of nature?

(a)Ecosystem
(b)Humans
(c)Vehicles
(d)Plants

Answer

Why

Correct — A. An ecosystem is defined as a functional unit of nature: a bounded space in which organisms interact with one another and with the physical environment around them.

The word carrying the question is functional. An ecosystem is the smallest level at which production, consumption, decomposition, energy flow and nutrient cycling all work together.

Humans, vehicles and plants are components, not units of function. None performs a complete function of nature on its own.

Why the others are wrong

(b)
Humans — Humans are one species inside an ecosystem, a consumer population. A single species cannot run an energy flow or cycle nutrients by itself.
(c)
Vehicles — Vehicles are man-made objects, not living components at all, so they have no place in the structure or function of a natural unit.
(d)
Plants — Plants are the producer component only. They capture energy, but without consumers, decomposers and the abiotic surroundings the unit is not functionally complete.

Concept

Ecological organisation runs organism → population → community → ecosystem → biome → biosphere.

An ecosystem has a structural side — its species composition and the vertical layering of the habitat.

It also has a functional side: productivity, decomposition, energy flow and nutrient cycling.

Because it takes in both the living community and its non-living surroundings, an ecosystem is self-sustaining in a way no single component is.

The phrasing is lifted straight from the standard textbook definition, so treat this as definition recall rather than an ecological judgement call.

Key facts

An ecosystem is a functional unit of nature in which organisms interact with each other and with their physical environment.
Its four functional aspects are productivity, decomposition, energy flow and nutrient cycling.
The levels of ecological organisation run organism, population, community, ecosystem, biome, biosphere.

Study next

Ecological pyramids of number, biomass and energy, and where each one invertsThe ten per cent law of energy transfer between trophic levelsBiotic and abiotic components: producers, consumers and decomposers

Common traps

Choosing 'plants' because plants sit at the base of every food chain — being essential is not the same as being a functional unit.
Reading 'ecosystem' as a place rather than as a unit of process.

SSC asks this as straight definition recall, inverted as 'the functional unit of nature is ___', or by asking which aspects of an ecosystem are structural and which functional.

Related PYQs

No directly related past PYQ was found.