Which of the following soil fertility improvement methods will have the most negative effect on the ecosystem if not controlled?

Organisms in an ecosystem are usually grouped according to their trophic level into__________

In the pyramid of energy illustrated above, the organism with the least amount of transferred energy is___________

Tall trees with unbranched trunks which grow above the upper storey of the forest are commonly referred to as _____

Maize grains are best stored against insect attacks by__________________