Answer:
Because they eat plants and other animals.
Explanation:
Food chain may be defined as the sequential steps of the tropic level in which an organism eats other organisms and itself eaten by other organisms. The producers are the autotrophs of the food chains.
Consumers may be defined as the organisms that depends on other organism for their food. Both penguins and blue whales eats plant and other animals in the food chain and thus acts as consumers. They cannot prepare their own food and eaten by other animals as well.
