Which effect of pollution does the photograph most likely show? A. Eutrophication
B. Sediment contamination
C. Ozone layer depletion
D. Desertification

What must be true for natural selection to heppen

Ialready know the answers to these questions and they are on the attachment. but i just need to know why that answer is the correct one. plz asap! this is for a report that i need to email by 10!

During the process of two rails or sides break apart and attract new nucleotide bases to form a new and complete strand.