Answer: option D - Understory
Explanation:
Understory refers to the layer of the rain forest LESS THAN 15% of sunlight.
Thus, it is a dark place (with low levels of light). And it houses many house plants.
Note that the other options receive ABOVE 15% of sunlight UNLIKE Understory.
So, option D is the right answer
I think the center or rain might been the most stable
concise verbal or mathematical statement of a relation that expresses a fundamental principle of science, like Newton's law of universal gravitation.