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.
Insulin controls blood sugar by lowering it, glucagon tells the liver to release its stored sugar into the blood stream, increasing blood sugar.
Chemical weathring is most rapid in areas that warm and wet.
Hope this helps !
Photon
Answer:
if you have headaches or migraines, your doctor may use a spinal tap to look for signs of infection, bleeding in the brain, to measure the pressure around your brain, or other things that could be causing your pain
Explanation:
