Identify the branch of biology that deals with the study of cells.

Cytology is the study of cells. It is a branch of biology that focuses on the structure, function, and behavior of cells, as well as their interactions with other cells and their environment. Cytologists use a variety of techniques, such as microscopy, to study cells and the organelles they contain. They also use techniques such as cell culture, flow cytometry, and molecular biology methods to study cells.