nature study vs inquiry

nature study and inquiry both are nouns.

Word	Noun	Adjective	Verb	Adverb
nature study	Yes	No	No	No
inquiry	Yes	No	No	No

As nouns, inquiry is a hypernym of nature study; that is, inquiry is a word with a broader meaning than nature study:

nature study: the study of animals and plants in the natural world (usually at an elementary level)
inquiry: a search for knowledge

Other hypernyms of nature study include enquiry, research.

nature study (noun)	inquiry (noun)
the study of animals and plants in the natural world (usually at an elementary level)	a systematic investigation of a matter of public interest
	a search for knowledge
	an instance of questioning