Answer:
B. Cells in Alex’s body underwent mitosis to create new tissue
Step-by-step explanation:
Mitosis is the cell division that forms two genetically identical daughter cells from one parent cell. It occurs in somatic cells and is responsible for the growth and development of individuals.
Alex gained the height as the cells in tissues of his body underwent the mitosis and produced new daughter cells. Repeated cycles of mitosis added a large number of new cells to his body to form new tissues in his body parts and caused an increase in his height.