A phospholipid is structurally similar to a triglyceride except that in a phospholipid, a charged phosphate group replaces one of the

The correct answer is - fatty acid.

Explanation:

A phospholipid is a one of lipid molecule which is present as major component of cell membrane, that plays a significant role. Phospholipids allow for selective passage of ions and other molecules through the cell membrane.

Phospholipid is structurally similar to triglyceride except that it is made up of two fatty acids instead of three fatty acid, in phosphoplipid third fatty acid is replace wit a phosphate group, however, glycerol molecule present in both.  The phosphate group of the phospholipid is negatively-charged which makes it polar or hydrophilic head, .

Thus, the correct answer is - fatty acid.