Why do the pocket mice in the dark lava environment have white underbellies?

They have a genetic mutation that affects their fur color. Why do dark-colored rock pocket mice on dark lava flows have white bellies? There is no selection for dark bellies by visual predators. ... -Mutations for advantageous traits are more likely to be passed on to the next generation.

Explanation:

the endomembrane system i think

the sun creates it's own light, also gives light and life to bunch of stuff like plants,animals,humans etc.photosyntesis is the process of making food which needs sun,water,nutrients etc.