Answer:
Because they are hydrophilic
Explanation:
The cell membrane is made up of a phospholipid bilayer. The phospholipid bilayer is made up of an arrangement of phosphate heads, which are (attracted to water) hydrophilic, and fatty acid tails, which are hydrophobic. (repelled by water).
Because they are attracted to water, the phosphate heads face the outside of the cell, where the water is
