biological science vs valency

biological science and valency both are nouns.

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

biological science (noun)	valency (noun)
the science that studies living organisms	(chemistry) a property of atoms or radicals; their combining power given in terms of the number of hydrogen atoms (or the equivalent)
	(biology) a relative capacity to unite or react or interact as with antigens or a biological substrate
	the phenomenon of forming chemical bonds