define a food web.identify a food web that may br operating in a fores ecosystem

Food web is a system of interconnected food chains. An example  of a web operating in forest ecosystem:- Grass is eaten by grasshopper which can be eaten by lizard or hawk. lizard is eaten by hawk. Grass can also be eaten by rabbit and frog which then eaten by hawk. Frog can also be eaten by snake and snake can be eaten by hawk.
Humans accumulate pesticides by eating plants or animals having that in their body.  Food chains are not isolated, but rather interconnected with each other.

An interconnected network of food chain, which forms a multitude of feeding connections among different organisms of a biotic community, is called a food web.