Principally chemists and physicists. However, the subject is also of interest to meteorologists (clouds have interesting structure, for instance), and biologists (the structures of DNA and other biologically significant chemicals are important), amongst others.
A chemist studies the composition, structure, properties, and changes of matter. They explore the elements, molecules, and compounds that make up substances and how they interact with each other.
Ahemist is the type of scientist that studies elements, atoms, molecules .
A mineralogist studies minerals.
An ecologist studies pollution
The kind of scientist who studies Urology would be a Biologist, since Urology concerns a biological function (urination). If you mean the kind of doctor who studies Urology, that would be a Urologist.
meteoroligists
Audiologist
An Ichthyologist.
Botanist
cosmologists
seismologist
a biologist