Answer:A.Combination probably
when a sperm cell joins with an egg, it's called fertilization
A. 50%Tropical rainforests, though covering only a small portion of the Earth's surface, are incredibly rich in biodiversity. They are estimated to be home to about 50% of the world’s species of plants and animals. This high percentage is due to the ideal climate and complex ecosystems found in rainforests, which support a wide variety of life forms.