Which of the following is a food chain in the food web, tree, deer, mountain lion, fox; grass, caterpillar, robin, hawk; grass, grasshopper, snake, hawk; tree, rabbit, hawk, snake

Food chain is a sequence of living organisms that eat one another. The goal is energy and nutrition flow in the ecosystem from one organism to another.
From the given options, the following are food chain in the food:
 grass -> grasshopper -> snake -> hawk
It is a linear pathway. The hawk eats snake, the snake eats the grasshopper and the grasshopper eats  grass.

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