What is so special about tropics that they account for a greater biological diversity?

All of these

a-Tropical lattitudes have remain undisturbed for millions of years and thus had a long evolutionary time for species diversification.

b-Tropical environments are less seasonal, relatively more constant and predictable.

c-More solar energy in tropics results in higher productivity ,thus accounting for a higher diversity.

d-All of these is the correct option .

Tropical lattitudes have remain undisturbed for millions of years and thus had a long evolutionary time for species diversification. Tropical environments are less seasonal, relatively more constant and predictable. More solar energy in tropics results in higher productivity ,thus accounting for a higher diversity.