A seismologist.
geologist
The name for this type of scientist is a teuthologist
A scientist who studies animal life is a zoologist. There is no particular name for a scientist that specialises in platypuses.
The type of scientist that studies the environment is an enviromentologist.
what scientist studies hydrogen and oxygen
Geologists study the Earth's interior. They also study the Earth's composition and all the processes that cause it to change.
A botanist.
An Entomologist
A zoologist.
Sedimentologist.
paleontologist
Meteorologists