Answer:
<h2>Earth's core.</h2>
Explanation:
<h2>hope this is useful </h2>
The organs listed above are all part of the excretory system except for the spleen and the <span>esophagus.
</span><span>The kidneys act to filter our blood, and remove wastes, which eventually pass out of us through urine,
The bladder acts to collect and store urine until it can be emptied through urination.
The ureter runs from the kidneys to the bladder whereas the urethra runs from the bladder to exit the body.</span>
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.
The feature that separates hominids from other primates is Complex social skills