Match the functional groups with their structures:

(choices are in the attached image)

-oh
-nh2
-ch3
-cooh

The true answer of your question is :

OH : HYDROXYL GROUP

NH2 : AMINO GROUP

CH3 : METHYL GROUP ( but in rather broader terms, that functional group of formula CnH2n+1 where n is an integer is called ALKYL GROUP where by substituting n by 1,2,3... we obtain methyl for n = 1, ethyl for n = 2, and propyl for n = 3 )

COOH : CARBOXYL GROUP is the correct answer since carbonyl is characterized by the presence of functional group C=O in general the formula of the compound would be
R-C=O-R’ where R and R’ are alkyl groups like methyl for example. However the carboxyl group could be thought of as a summation of carbonyl + hydroxyl ( CO + OH ) resulting thus in COOH.

I hope you’ll understand everything, anyway if not i’m always here to help. ♥️