Answer:
Many proteins exchanges between cytoplasm and nucleus.
Explanation:
Proteins such as importins and exportins exchanges between cytoplasm and nucleus because of their need in these two sides. Importins are the proteins which enters in the nucleus from cytoplasm due to need for the nucleus while on the other hand, the exportins proteins exit the nucleus and enters the cytoplasm because they are formed in nucleus and needed by the cytoplasm of the cell.
