Which of the following is most likely to be a limiting factor for growth on the floor of a tropical rainforest?
(a) water
(b) shelter
(c) sunlight
(d) prey

The correct answer will be option-(C) sunlight.

Explanation:

A limiting factor is the factor which directly controls the growth of the plant  and if its amount is lowered or becomes negligible will limit the growth of the population.

The tropical rainforest is a type of forest with species richness which is identified with very dense canopies. It is impossible for the sunlight to reach the ground surface of the forest so, plants have evolved and adapted there to receive maximum sunlight by increasing their length.

Thus, option-C is the correct answer.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.