How do you think this food web would be affected if the plants were eliminated

If plants were eliminated from the food web, the food web would collapse as plants play a very important role in the food web. plants are primary producers in a food web; they convert water, sunlight and carbon dioxide into carbohydrates. they transfer the energy from the sun to the primary consumers, then to the secondary consumers and to the tertiary consumers and so forth. thus they are the energy source in a food web, without which the food web won't exist in the first place.

The hawk receives 0.1% energy from the caterpillar although the caterpillar gets eaten by another bird smaller than the hawk first

The answer is b) gene