I do believe that it is C. crossing over :) I hope that is correct, it seems like the only plausible answer.
Answer:
B) increased exchange surface provided by their membranes
Explanation:
Alveoli are tiny air sacs that are responsible for exchanging oxygen (O2) and carbon dioxide (CO2) in the lungs. Alveoli have elastic fibers in order to expand and recoil depending on the volume of air breathed in. The alveolar epithelial cells (pneumocytes) may adopt a shape that serves to increase the surface area of gas exchange. On the other hand, intestinal epithelial cells have microvilli, which are microscopic projections in the plasma membrane. Microvilli serve to increase the cell's surface area, thereby facilitating the absorption of nutrients and water.
They both reproductive Pacific cells
Bacteria is good, but there is some bad. in this case, your talking about your digestive track therefore, this is good bacteria and what bacteria does is it breaks down the stuff that your body cannot break down by itself so the answer is C I hope this helped and I hope it was the branist answer