Answer:
solids are more tightly packed together (the molecules) than liquid or gas so it allows it to travel through vetter/faster
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.
found that animals are composed of cells is Theodor Schwann
found that plants are composed of cells is Matthias Schleiden
looked at cork through a compound microscope is Robert Hooke
declared that all living cells can only come from other living cells called living cells "animalcules" is Rudolph Virchow