B- tree > insect > frog> snake> hawk
The food chains are represented by organisms interconnected by red arrows that point in the direction of the one that's eating. So, the relation that is explicit by the arrow is that the organism from where the arrow departs is eaten by the organism where the arrow is pointing towards to. So, the food chain that can be observed accurately in the food web is: the tree is eaten by the insect, the insect is eaten by the frog, the frog is eaten by the snake, and the snake is eaten by the hawk.