Regulation of a system by the output.
Answer:
Scientists believe that the different types we know emerged as early humans adapted to infectious diseases.
Explanation:
Different human blood types probably emerged to ward off infectious diseases. The incompatibility of some blood types, however, is only an "accident" of evolution. But this is a relatively recent problem, since blood transfusion has been around for only a few hundred years.
There are four main blood types. The oldest is B, which must have originated about 3.5 million years ago - it existed even before the human species evolved from its hominid ancestors, from a genetic mutation that modified one of the sugars in the surface of red blood cells.
Approximately 2.5 million years ago, mutations inactivated sugar, resulting in type O blood, which has neither type A nor B. sugar. AB blood, as it is easy to suppose, is covered by both sugar A and sugar by B.
Answer:
It is easier to send the raw materials to the factories to become finished goods.
Explanation:
I don't know if this was multiple choice, but you would put the farmland upstream from the factories so that the crops and other raw materials could easily go down to the factories to be finished. I hope this helped :)
I've checked all the options and I think that the right answer looks like this: M<span>ollusks</span> have highly developed olfactory receptors.
