He was playing the lead role in that story.

He is receiving training as a reserve soldier.

He was the one who set fire to this project.

The activity of brain cells directly affects our thoughts and actions.

Cytology is a branch of biology that studies the structure and function of cells.

Stem cell research is opening up new frontiers in medicine.

The cell nucleus holds genetic information.

The cell membrane plays an important role in maintaining the structure of the cell.

Cell division is one of the basic processes of life.

Germ cells play an important role in the reproduction of organisms.