The correct option is D High rainfall and high temperature
The characteristic of tropical rainforests is the hot, moist and large amount of precipitation or rain, that falls each year. It rains year-round in tropical rainforests, with most receiving over 100 inches of rain per year. The second defining characteristic of tropical rainforests is their annual temperature, which is normally between 70−900F. Tropical rainforests are able to maintain high species richness of plants due to a large amount of rainfall and warm conditions. Thus, the correct answer is option D.