answer:
by having a high genetic level of melanin in your skin, you're skin is more protected from the ultra violet sun rays. Darker skinned races have more melanin present, these races originate from hot countries where sunlight is often present; the production of melanin in their skin allows them to reflect and inhibits they're skin from becoming extremely damaged. Light skinned races don't have a large amount of melanin due to they're native countries lacking sunlight. This is an evolutionary adaptation of the human race.
Fossil record of the first possible bipeds is the evidence exists that state humans are evolved in Africa. Modern humans arose in Africa at least 250,000 to 300,000 years ago, fossils and DNA are the evidence that reveals. Scientists have been unable to pinpoint a more specific homeland because the earliest Homo sapiens fossils are found all across Africa.
Humans first evolved in Africa, and much of human evolution occurred on that continent. The fossils of early humans who lived between 6 and 2 million years ago come entirely from Africa. Most scientists currently recognize some 15 to 20 different species of early humans found from Africa.
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For body cells to function properly, the following conditions need to be balanced:
1. BLOOD SUGAR
2. BODY WATER
3. BODY TEMPERATURE.
These three factors have to be in the right proportion for the cells and the body as a whole to function properly and to maintain homeostasis.
Blood sugar is the source of energy in the cell and it is required by all cell for carrying out the normal biochemical reactions in the body. The biochemical reactions in the body use water as a medium of reaction, thus the water balance in the body must be maintained. The body temperature also need to be kept at the normal level or else the normal biochemical reaction of the body will not be able to take place, due to the fact that incorrect temperatures deactivate the enzymes that mediate biochemical reactions.
Answer:
X: Positive gravitropism
Y: Negative gravitropism
Explanation:
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Answer:
They are modified by shape, function, or size. They are made to have certain roles in different parts of our bodies. These cells group together to make/form tissues. Then these tissues make up organs that we obviously need. Different specialized cells include blood cells, nerve cells, and reproductive cells.
Explanation:
