What is the most likely consequence for a human of not spending at least 20 minutes a day with a portion of one's skin exposed to the sun?

Describe the iron sulfide hypothesis and the lipid membrane hypothesis.

What is the difference between bacterial infections and viral infections?

How does the molecular clock work? a. it analyzes the brain functionality of two different species.b. it examines and compares the physical characteristics of two different species.c. it illustrates relationships between two different species.d. it compares the number of mutations that exist in the dna of two different species.