The process of moving through a system and returning to the starting point

How does the study of genetic disorders such as pku biologists understand normal alleles?

Ecologist have observed a sharp increase of sulfur dioxide in the air . what might be a possible consequence of excessive sulfur dioxide in the air ? a. acid rain b. ozone layer depletion c.ozone layer hole d.increase in sea levels

What enzyme is most important for dna replication and why?