persistent vs biology

persistent is not a noun while biology is a noun.

Word	Noun	Adjective	Verb	Adverb
persistent	No	Yes	No	No
biology	Yes	No	No	No

persistent (noun)	biology (noun)
	the science that studies living organisms
	all the plant and animal life of a particular region
	characteristic life processes and phenomena of living organisms

persistent (adjective)	biology (adjective)
retained; not shed
never-ceasing
stubbornly unyielding
continually recurring to the mind