The group linkage present in fats is:

Ester linkage

The answer is (2) ester linkage.

Fats are a type of lipid that is composed of three fatty acids attached to a glycerol molecule. The fatty acids are linked to the glycerol molecule by ester linkages. Ester linkages are formed when the carboxyl group of a fatty acid reacts with the hydroxyl group of glycerol.

Peptide linkages are formed between amino acids, and glycosidic linkages are formed between sugars. Neither of these types of linkages are present in fats.