What is the relationship between uv radiation and skin color

Which of the following is a macronutrient? carbohydrates lipids amino acids all of the above

Why does it matter if osmosis is put into a “scab” or a “nosebleed? ” where would that leave him?

Scientists discover two populations of mice on either side of a major river. the two populations have almost identical genes but the mice from one side cannot breed with mice from the other. this is most likely because