biology vs microbiology

biology and microbiology both are nouns.

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

As nouns, microbiology is a hyponym of biology; that is, microbiology is a word with a more specific, narrower meaning than biology:

biology: the science that studies living organisms
microbiology: the branch of biology that studies microorganisms and their effects on humans

biology (noun)	microbiology (noun)
the science that studies living organisms	the branch of biology that studies microorganisms and their effects on humans
all the plant and animal life of a particular region
characteristic life processes and phenomena of living organisms