Moving thing in and out requires surface area, many small cells have much more surface area for much less volume than one big cell so it is more efficient.
Answer:
Because virus are just sticking into the human
cell membranes
Living things obtain and use energy so alive?
As electrons move down the chain, energy is released and used to pump protons out of the matrix, forming a gradient. Protons flow back into the matrix through an enzyme called ATP synthase, making ATP. At the end of the electron transport chain, oxygen accepts electrons and takes up protons to form water.