What is an ion pump??

Active transporters or ion pumps are transporters that convert energy from various sources—including adenosine triphosphate (ATP), sunlight, and other redox reactions—to potential energy by pumping an ion up its concentration gradient.

Explanation:

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.

the missing space is phylum