Mitosis occurs only in multicellular organisms.

Explanation

**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 often referred to as equational division because the chromosome number remains constant throughout the process.

2. **Clarifying the Statement**: The statement claims that mitosis occurs only in multicellular organisms. This is incorrect. Mitosis can occur in both unicellular and multicellular organisms.

3. **Examples of Unicellular Organisms**: In unicellular organisms, such as bacteria, mitosis is involved in asexual reproduction. During this process, the single parent cell divides to produce two identical daughter cells, maintaining the same chromosome number.

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