Answer:
a. cytology
Explanation:
Cytology is a branch of biology that deals with the study of the cell. The study of the cell include the anatomy (structure), physiology (function), chemistry (reactions), etc.
Option b is incorrect. Genome is the total genetic component of a cell or an organism.
Option c is incorrect. Pathology is a branch of medical science that deals with the study and diagnosis of diseases.
Option d is incorrect. The nucleus is an organ within the cell that contains the bulk of the genetic components of the cell and hence, controls a lot of the cell's activities.
The correct option is a.
