food chain is-

A food chain is defined as a linear sequence of organisms through which nutrients and energy pass as one organism eats another [1]. It represents a sequence where one organism becomes food for the next, starting from producers (autotrophs) and ending with top carnivores [2]. This process facilitates the transfer of energy and nutrients among organisms within an ecosystem [1]. While autotrophs at the first trophic level fix solar energy, this energy is then made available to heterotrophs or consumers through feeding [3]. Thus, the food chain essentially traces the passage of food and the corresponding unidirectional flow of energy from one biotic level to another [5]. Unlike a food web, which illustrates all possible energy transfers, a food chain focuses on a single pathway of this energy flow [1].

Sources

1. [1] https://www.elearning.raghunathpurcollege.ac.in/files/37D4E18E16675739241.pdf
2. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > 2.2. FOOD CHAIN > p. 11
3. [3] Science , class X (NCERT 2025 ed.) > Chapter 13: Our Environment > 13.1.1 Food Chains and Webs > p. 210
4. [5] Science , class X (NCERT 2025 ed.) > Chapter 13: Our Environment > 13.1.1 Food Chains and Webs > p. 211