the cell membrane regulates the amount of water and other molecules as they pass into or out of the cell. What is this balance between the water on the inside and outside of the cell called?

Pentane with molecular formula c5h12, exists in three isomeric forms. one shows linear carbon chains, another has one -ch3 groups present on the third carbon atom, and the third has two -ch3 groups present on the second carbon atom. what types of isomers are these? a. geometric isomers b. structural isomers c. halotropic isomers