Food chain

Every food chain starts with producers. These are green plants and some bacteria that make food using sunlight. Consumers come next. They eat the producers, or eat other consumers. Each step in the chain is a trophic level.

Energy flows in one direction only. It does not go back from the herbivores to the plants, or from the plants to the Sun. Some energy is lost at every step. So food chains usually have only three or four steps.

In nature, each living thing is eaten by two or more kinds of others. So food chains cross and branch. The branching pattern is called a food web.

A small example

NCERT asks which group makes a food chain. Grass, wheat and mango do not, since all 3 are plants. Grass, goat and human do. That chain has 3 steps: grass is the producer, the goat eats grass, and the human eats the goat.

Where marks go

Question 14 of CBSE's 2026-27 Science sample paper is a 3-mark question on a food chain. Part B asks if the chain could have three more trophic levels. The board's Science marking scheme for 2026-27 answers no, with the reason. So much energy is lost at each step that very little usable energy would be left.

The question says "Justify", so a bare "No" does not answer it. The reason is what the question asks for. See where the marks go in CBSE Science.

About the author

Deepti Sardana

Founder Member & Academic Lead

An IIT alumna (M.Sc., M.Phil.) with over 25 years in teaching, child psychology and learning assessment. As Academic Lead at EduBrahma, she leads the method TRUtesting uses to find where and why a child loses marks.

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