An investigator who conducts an experiment to determine how changes in pH affect the function of enzymes on digestion is most likely to be a (n) :

Biochemist

Explanation:

Biological chemist studies chemical processes in living organisms. They study the DNA, cells, proteins and how they relate to each other. Their duties includes conducting research for product and biological system developments in research institutions, present their findings for research grants. Biochemists also study the immune system, gene expression, and mutations that leads to cancer.