biology vs depressed

biology is a noun but depressed is not a noun.

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

biology (noun)	depressed (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)	depressed (adjective)
	filled with melancholy and despondency
	lower than previously
	flattened downward as if pressed from above or flattened along the dorsal and ventral surfaces