Because Africa is so small it is not environmentally diverse: the climate is roughly the same throughout the continent

African continent

Explanation:

Africa is not environmentally diverse because of its geographical condition which is hot in climate. Environmentally diverse is only possible when there is indices of biodiversity, including a large number of endemic species. In Africa countries like the Democratic Republic of Congo and South Africa which has five groups of animals: fish, birds, amphibians, mammals, and reptiles along with different species of plants (flora) and trees.

The climate is roughly the same throughout the continent which is dominated by desert conditions: a semi-arid climate. The central portion of the continent is more humid, with grasslands,  rainforests.

d is the best answer for this question.