The correct answer is (c) cell membrane.
Phosphorous is the second most important component in the body after calcium. The purpose of cell membrane is to hold the different components of the cell together and protect it from the outer environment. There are two important parts of phospholipids. The head region and tail region. The head region is a phosphate molecule which is hydrophilic in nature and the two tails are made up of fatty acids which are hydrophobic in nature. When the cell membrane is exposed to watery environment mixed with electrolyte, the phosphate group faces the watery environment and the tails hideaway being hydrophobic in nature. This helps in transportation of polar and non-polar molecules across membrane. Besides this function phosphorous is also a structural component of bones and teeth (calcium phosphate).
