Answer:NH2 group
Step-by-step explanation:
The NH2 group, is the group that conform the amines groups. Also, in organic chemistry, this gruop is the base and in the most common reactions works like that, for example:
R-COOH + R'-NH2 ---> RCOO-NH-R' +H2O
The amine group reacts with carboxylic group and produce a salt and water