Identify and name the functional groups present in the following compounds.
$(a)$ $CH_3-CO-CH_2-CH_3$
$(b)$ $CH_3-CH_2-CH=CH_2$

(A) The structure $CH_3-CO-CH_2-CH_3$ contains a carbonyl group bonded to two carbon atoms,which is characteristic of a $\text{Ketone}$ functional group.
$(b)$ The structure $CH_3-CH_2-CH=CH_2$ contains a carbon-carbon double bond,which is characteristic of an $\text{Alkene}$ functional group.