As humans dispersed from the equator peoples skin got lighter and lighter because of fewer exposure to sun radiation.
They didn't get tanned as much :)
Answer:
Myelin
Explanation:
Myelin is a fatty substance that surrounds nerve cell axons to insulate them and increase the rate at which information is passed along. The myelin can be compared to the protective coating of an electrical wire.
I don't know search on Google
Answer:
an area within the visual field wherein the cell will fire if the target appears.
Explanation:
In order to accomplish this, the researcher will need to specify an area within the visual field wherein the cell will fire if the target appears. This is because there are about 100 billion neurons in the human brain and each of them fires at a speed of about 200 times per second, thus making it impossible to define the receptive field of a particular neuron without highlighting a specific area of that neuron and visualizing that specific neuron.
between the Euphrades river and the tigris river
