Question

Assertion [A]: Food chains start with photosynthesis and end with decomposition.
Reason [R]: In an ecosystem, plants produce food and decomposers help in the decay of dead matter.

• A. Both A and R are true and R explains A
• B. Both A and R are true R does not explain A
• C. A is true and R is false
• D. Both A and R are false

Answer 1

The correct option is A Both A and R are true and R explains A

In an ecosystem, life is directly or indirectly dependent on plants for food because they are the only ones who can synthesize their own food and are also called autotrophs. So in any food chain, the first trophic level is of the producers i.e plants. Ultimately living organisms die and decay.
The decomposers help to clean the dead and decaying organic matter. The decomposers or saprotrophs are the bacteria and fungi that help in the decaying of dead matter. Their major source of energy is dead remains of producers and consumers.
In the process of extracting nutrients and energy from this dead material, they decompose them into small organic molecules and inorganic compounds that are released into the environment for reuse as raw materials by the producers and ensure the recycling of nutrients in the ecosystem.