Answer:
A is the polar, hydrophilic end.
B is the nonpolar, hydrophobic end.
Step-by-step explanation:
This type of molecule is mainly used to make cell membranes. The polar, hydrophilic end interracts with the inner and outer environments of the cell (the cell membrane is usually a bi-lipid layer) because they are mainly water. The nonpolar, hydrophobic end is sandwiched in between the hydrophilic ends away from water.