Human skin color likely represents a locally adapted compromise between?
1) the need to block UV radiation that causes cancer and the need to absorb sunlight for heat.
2) the need to block UV radiation that destroys folate and the need to synthesize vitamin D.
3) the need to block UV radiation that destroys folate and the need to absorb sunlight for heat.
4) the need to blend in with the environment and the need to absorb sunlight for heat.
