The word mature is an adjective.
It can also be a verb as in to gain experience or wisdom.
The part of the brain that matures late is the front part. This part of the brain is responsible for organizing thoughts, the interpretation of emotions and assuming responsibility.
The part of the cerebral cortex that matures first is the part that controls physical movement.
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
adverb
what part of speech is beneath
The part of speech for "unfamiliar" is an adjective.
The part of speech of "came" is a verb.
The part of speech for "twirl" is a verb.
The part of speech for "explicit" is an adjective.
The part of speech for "indefinite" is an adjective.