subaquatic vs biological science

subaquatic is not a noun while biological science is a noun.

Word	Noun	Adjective	Verb	Adverb
subaquatic	No	Yes	No	No
biological science	Yes	No	No	No

subaquatic (noun)	biological science (noun)
	the science that studies living organisms

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