Answer:
The correct answer is: geography and UV radiation.
Explanation:
Skin variation occurred thanks to evolution, and was driven as a consequence of the geographical location of different populations of humans.
The humans that lived in hot and sunny places, closer to the equator, where much more exposed to the sun's ultraviolet radiation. In order to survive the amount of UV lights that they were exposed to, new humans in those regions were being born with a darker skin tone, which was rich in melanin (a brown pigment that protects us from the sun radiation).
Contrary to these humans that lived in the tropical areas, the humans that populated the areas that were closer to the poles, developed much lighter skin as a result of lower amounts of melanin in their skin. Since sun exposure in the poles is very limited, humans needed to receive as much as they could for the production of Vitamin D, and thus, their skins got lighter and less protected.
Answer:
As part of the phosphate group, it is a component of DNA, RNA, ATP (adenosine triphosphate), and the phospholipids that form all cell membranes.
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Answer: Subarachnoid
Explanation:
The space in the meninges below the arachnoid membrane and above the pia mater contains the cerebrospinal fluid. Cerebrospinal fluid is produced by choriod plexus( a cluster of capillaries) from the blood. Blood vessels traveling within the subarachnoid space deliver oxygen and nutrients to the spinal cord.
Answer:
Space telescopes can carry instruments to observe objects emitting various types of electromagnetic radiation such as visible, infrared or ultraviolet light; gamma rays; or x-rays. X-ray telescopes, such as the Chandra X-ray Observatory, use X-ray optics to observe remote objects in the X-ray spectrum.
Explanation:
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