Horizontal gene transfer can occur through several mechanisms. why is this relevant to humans

Explanation:

Horizontal gene transfer helps in acquiring relevant gene that are not present in cell but are beneficial.

If a gene is lost in the cell, through gene transfer it can be regain and the various adverse effect caused through the absence of the gene can be reversed.

It also help in treatment of various disease such as cancer by introducing into the body non cancerous cells and prevent the spread of cancerous cells .

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.

i believe the answer would be b. hope it : )