Question

how can we say that movement of nutrients is cyclic in a food chain?

Answer 1

Water, carbon-dioxide and nitrogen are taken by the plants from the soil and convert into food. This food is taken by the herbivores and carnivores in turn. And when the plants and animals die and decay the materials such as water, carbon and nitrogen present in their bodies are returned back to the soil and air, from where they were taken initially. And then these materials are used to produce new plants. So nutrients are cyclic in food chain.