Today I will talk about food chain.
Food chains are often used in ecological modeling. Food chains vary in length from three to six or more levels. A food chain consisting of a flower, a frog, a snake and an owl consists of four levels; whereas a food chain consisting of grass, a grasshopper, a rat, a snake and finally a hawk consists of five levels. All food chains must start with a producer. All organisms in a food chain, except the first organism, are consumers.