This is an example of the sea floor spreading
The white matter is white because of the fatty substance that surrounds the nerve fibers.
All you need is to locate an artery. theres one by your neck, on the the far sides of your wrists, between your thighs, or you could just feel your own heart.
Answer:
A group of individuals of the same species occupying a particular geographic area. Populations may be relatively small and closed, as on an island or in a valley, or they may be more diffuse and without a clear boundary between them and a neighboring population of the same species.
