His class is dull, and the students are bored.

Please use the emergency stairs in case of a fire.

Due to the earthquake, the city declared a state of emergency.

In biology class, I learned about meiosis.

The meristem of this plant is very active.

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.