cytology vs biological science

cytology and biological science both are nouns.

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

As nouns, biological science is a hypernym of cytology; that is, biological science is a word with a broader meaning than cytology:

cytology: the branch of biology that studies the structure and function of cells
biological science: the science that studies living organisms

Other hypernyms of cytology include biology, microscopic anatomy.

cytology (noun)	biological science (noun)
the branch of biology that studies the structure and function of cells	the science that studies living organisms