The most plausible hypothesis is: Tropical regions generally have more available water and higher levels of solar radiation. They also have very high rates of immigration and very low rates of extinction.
explanation:
Water is essential for an abundance of life, and sunlight is the means by which the whole food chain receives energy. Plants convert the sunlight into food, herbivores eat them, and other animals eat herbivores.
Hope this helps, and muchas luck on your biology.
A balance of organic and inorganic materials
DNA is a chain of nucleotides bonded together. On that chain there are particular portions of it that the sequence of the nucleotide codes for particular proteins; this is known as a gene. In eukaryotric cells, DNA is coiled around proteins such as histones to form chromatids which when two join at the centre by a centromere to form a chromosome.
Why is the active site specific for only one type of substrate? Enzymes have a lock and key type fit so only a specific substrate fits in the activation site.
