Ans. (B).Cells in Alex’s body underwent mitosis to create new tissue.
Mitosis is defined as a type of cell division, which is associated with the growth, development, and repairing of damage tissues. During mitosis, one parent cell gives rise to two identical daughter cells. As mitosis increases the cell numbers and makes new tissues, it is responsible for growth and development of the body.
Thus, the correct answer is option (B).