Which branch of biology is concerned with the study of cells?

Cytology is the branch of biology that focuses specifically on the study of cells. This field involves examining cell structure, function, and the interactions between various types of cells. Researchers in cytology may explore how cells grow, reproduce, and respond to their environment, as well as how various diseases affect cellular function.

Understanding cells is crucial because they are the fundamental unit of life; everything from the basic processes of metabolism to the complex functions of multicellular organisms is rooted in cellular activity. By studying the characteristics and behaviors of cells, scientists can gain insights into larger biological systems, including how tissues and organs function.

The other branches mentioned do not focus primarily on cells. Anatomy is concerned with the structure of organisms and their parts; ecology studies the relationships between organisms and their environments; and physiology examines how living organisms function and the physical and chemical processes that occur within them. While these fields may intersect with cytology at times, their main focus lies elsewhere, which distinguishes cytology as the correct answer for this question.