OPTIONS: 1. The number of individuals. 2. sub-units of species. 3. the Arctic. 4. different organisms' numbers. 5. ice. 6. biological diversity. 7. penguins. 8. heat and light.
Given those answer options, answer the question: Fact 1: Biodiversity generally increases from the poles to the equator. Fact 2: Biodiversity is equated with the number of different organisms present in a habitat . Given the two facts above, what increases in habitats from the poles to the equator?
A:
4.