Answer:
cell membrane is the outer boundary present around the cells functions to protect the inner cellular material from outer invaders and maintain the shape of cell
Explanation:
Cell membrane is the outer most boundary made up of lipids and proteins.
Mainly the membrane is composed of lipid bilayer in which protein chains are embedded
It is best defined as a "proposed explanation".
First is the second and the other one is the 4th
creatine phosphate is the chemical that helps to regenerate ATP