I am confident that the answer should be.....<span>A protein acts as a pump and moves calcium ions from an area of low concentration to an area of high concentration.
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Explanation:
Solar UV radiation. Australia experiences some of the highest levels of UV radiation in the world because we are close to the equator and have many clear, blue-sky days. The Earth's orbit also brings countries in the southern hemisphere (Australia included) closer to the sun in the summertime than countries in the northern hemisphere during summer.
Answer:
Protons are positive while nuetrons are negetive.
Expland nation:
The answer is; the melanin in darkly pigmented skin protects DNA from UV radiation, and UV radiation can cause skin cancer
In Africa, due to its equatorial latitude location, receives direct sunlight at more or less 90 degrees most of the year. These highly concentrated rays increase the UV radiation exposure that can cause damage to cell DNA. Selection pressure, therefore, favored individuals with high melanin concentrations that protect against UV. Therefore population evolved towards high melanin densities in the skin.