Answer: C. Histologist
Explanation:
A cell biologist refers to a person who studies cells and their functions and their interactions with the biological organisms.
A taxonomist refers to a biologist who classifies organisms into their categories.
A histologist, can also be called a histotechnician, and this is someone who prepares tissue samples for the pathologist to study. A histologist cut samples from organs which are used for microscopic tissue analysis.
Palaeontologist is a person who studies fossils in order to get information regarding life on Earth.
The dissolved oxygen content in water
Answer: radiation i think