A distinctive and characteristic functional group of fats is
A. A peptide group
B. An ester group
C. An alcoholic group
D. A ketonic group

Hint: To answer this question we have to know about fats. The fat present in an animal or human body is also called the energy bank of the body as it stores food and energy.

Complete Step by Step Solution:
Fat is a nonpolar substance. It is composed primarily of hydrocarbons. It can be both hydrophobic and lipophilic. Fats are usually flammable and surface active substances. Most of the fats are unsaturated lipids that are present as a solid at room temperature. Both fat and oil are made of glycerol. Fat stores the food and energy of our body. It is a lipid. On oxidation one gram of fat gives approximately \[37KJ\] of energy which is much higher than energy produced by carbohydrates.

The fats present in our body are also known as triglycerides. These triglycerides are actually the tri esters of fatty acid along with the glycerol. Thus fat contains ester groups. Thus we can write that a distinctive and characteristic functional group of fats is an ester group.
Thus the correct option is B .

Note: On reduction lipid breaks into fat. Fat acts as the energy bank in our body. Fat is solid lipid. It is generally present below the dermis of our skin as subcutaneous fats.