Amembrane that allows onaly some materials to move in and out of the cells is

The cell membrane is selectively permeable, allowing only certain substances to pass through. Passive transport is a way that small molecules or ions move across the cell membrane without input of energy by the cell. The three main kinds of passive transport are diffusion, osmosis, and facilitated diffusion.

explanation:

on disadvantage of hydroelectric power is the cost. another disadvantage of using hydroelectric power is finding a water source powerful enough to harvest hydroelectric power.

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex