I believe this is more like an opinion, I would pick D.
The answer to the question are superclusters.
Answer:
the cell membrane.
Explanation:
controls what materials go into and out of the cell. For example, the cell membrane allows nutrients and oxygen to move into the cell, and carbon dioxide and waste materials to move out of the cell.
The absorptive cells lining your small intestine create a barrier between your gut and your bloodstream. The amino acids resulting from protein digestion must travel across this barrier so they can enter your blood and travel to the cells throughout your body.