Mitosis is

Options

A. Equational division
B. Reductional division
C. Heterotypic division
D. Always absent in a zygote

Answer

### Step-by-Step Solution:

1. **Understanding Mitosis**: Mitosis is a type of cell division that results in two daughter cells that are genetically identical to the parent cell. It is primarily involved in growth, repair, and asexual reproduction.

2. **Types of Cell Division**: There are two main types of cell division:
- **Equatorial Division (Mitosis)**: This type of division maintains the same chromosome number in the daughter cells as in the parent cell. For example, if the parent cell is diploid (2n), the daughter cells will also be diploid (2n).
- **Reduction Division (Meiosis)**: This type of division reduces the chromosome number by half. For example, a diploid parent cell (2n) will produce haploid daughter cells (n).

3. **Clarifying Terms**:
- **Equatorial Division**: Refers to mitosis, where the genetic material is equally divided.
- **Reduction Division**: Refers to meiosis, where the chromosome number is halved.

4. **Mitosis in Zygote**: The statement that mitosis is absent in the zygote is incorrect. The zygote undergoes mitosis to develop into a multicellular organism. Therefore, mitosis is essential for the growth and development of the zygote.

5. **Conclusion**: Based on the definitions and explanations above, the correct answer to the question "Mitosis is" is **Equatorial Division**.