Answer:
melanin affects how one looks (1st question)
cause and effect (2nd question)
Explanation:
for the 2nd question, its cause and effect because uv rays hit our skin and our skin is affected which gives us suntan.
Im not really sure , but it might have something to do with polar chemical compound <span />
There aren't enough oxygen molecules in the air are higher altitudes
B, because in all truth and honesty, stress is truly inevitable. Also, use process of elimination. I hoped that helped :)
