The annual precipitation varies most in which of these ecosystem?

The annual precipitation varies most in tropical rain forest ecosystem.

Explanation:

Tropical rain forest is one of the most extensive selvatic ecosystems, with a very dense vegetation, which is characterized by its high temperatures and abundant and varied annual precipitations, which are between 1500 and 5000 mm per year.

This ecosystem can be found in Central America, Mexico, Australia and even in Asia, where a seasonal climate can be seen divided into rainy seasons -which register the highest rainfall- and a dry season, where rainfall is lower. Most of the year the climate is hot and one of its characteristics is to present the greatest variety of animal and vegetable species.

Tropical rain forest link

the answer to your question is:

c. complementary base-pairing