In the hypothetical food chain consisting of grass, grasshoppers, sparrows, and hawks, the grasshoppers are classified as b) primary consumers.
This is because primary consumers are organisms that eat primary producers, which in this case are the grasses. Grasshoppers consume the grass to obtain energy, placing them directly above the producers in the food chain. They play a crucial role in transferring energy from the producers (the grass) to the secondary consumers (the sparrows) that feed on them.
Understanding these roles is vital in ecology, as it helps us grasp how energy flows through an ecosystem and the interdependence of organisms.