D. A large continent with many different geographic features and climates.
Africa is the second-largest continent in the world, covering approximately 30 million square kilometers. It is home to a wide variety of landscapes and ecosystems, including vast deserts, tropical rainforests, grasslands, savannas, and mountain ranges. Africa is also home to many of the world's largest rivers, including the Nile, the Congo, and the Niger. Its diverse geography has led to the development of many unique plant and animal species, making Africa a continent of great biodiversity.