A biologist studies living things, like plants and animals
and microorganisms.
Biologists examine the whats, wheres, whens, whys
and hows of these creatures. Ditto, for their requirements to stay
alive-and-kicking and make seeds or eggs or whatever else it takes to produce a
new generation.
Molecular biologists
study the size, shape, function and other properties of molecules like DNA
(deoxyribonucleic acid)--an organism's genetic code book--and important
substances like protein.