Which group of organisms together will not form a food chain?
I. Grass, lion, rabbit
II. Plankton, leopard, hawk
III. Lion, grass, snake, tiger
IV. Frog, snake, eagle, grass, grasshopper
Group II contains hawk and leopard as consumers. Both hawk and leopard do not feed directly on planktons (the producers). Thus, a food chain cannot be formed in this case.
Snakes, tigers and wolves are carnivorous, they never feed on grass. So, a food chain cannot be formed by group III as well.