A membrane is permeable to hydrogen but not to sodium ions. Which molecule cannot move into the cell? A. Both hydrogen and sodium cannot move into the cell
B. Hydrogen
C. Sodium
D. Both hydrogen and sodium can move into the cell

a polymer is a chainlike molecule made up of small molecular units. these small molecular units are called monomers. monomers of polymer can be joined together either naturally or synthetically.  

c. establishing proper sleep hygiene

im not intirely sure but i think the anwser is d relative humidity