If you add the amount of protons with the amount of neutrons, you get the atomic mass. Sodium has 11 protons, and 12 neutrons. 11+12=23
They help the plant stand straight and they also hold water in them. hope this helped! ^^
The polar head of a phospholipid is made of phosphate. The polar head has a negative charge that is made up of phosphate molecules. This polar region attracts water and is positioned outward to interact with the water.
I hope this helps!
