biology vs subaquatic

biology is a noun but subaquatic is not a noun.

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

biology (noun)	subaquatic (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

biology (adjective)	subaquatic (adjective)
	partially aquatic; living or growing partly on land and partly in water
	growing or remaining under water