In which structure the cells divide by mitosis only ?A Ovary B Root tip C Anther D Testis

The structure in which cells divide by mitosis only is the Root tip (B).

Here's a step-by-step explanation:

1. Mitosis is a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.

2. In animals, mitosis occurs in all somatic (non-sex) cells. In plants, mitosis occurs in areas of growth, such as the root tips and the tips of stems (also known as apical meristems).

3. The ovary (A), anther (C), and testis (D) are all involved in sexual reproduction and therefore involve meiosis, a different type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell. This is crucial for the production of gametes (sex cells) and genetic diversity.

4. Therefore, the root tip (B) is the structure where cells divide by mitosis only.