Fractional change in number of chromosome is called

Options

A. Euploidy
B. Aneuploidy
C. Parthenogenesis
D. All of these

Answer

### Step-by-Step Solution:

1. **Understanding Chromosome Changes**:
- Chromosomes are structures within cells that contain DNA. Each species has a specific number of chromosomes that are essential for normal physiological functions.

2. **Types of Chromosomal Changes**:
- When there is a change in the number of chromosomes, it can be classified into different types:
- **Aneuploidy**: This refers to a condition where there is an abnormal number of chromosomes, which can be either more or less than the normal set. It is a fractional change in the number of chromosomes.
- **Uploidy**: This term refers to the normal condition where the organism has the correct number of chromosomes.
- **Parthenogenesis**: This is a form of asexual reproduction where an organism develops from an unfertilized egg. It is not directly related to changes in chromosome number.

3. **Identifying the Correct Term**:
- The question specifically asks for the term that refers to a fractional change in the number of chromosomes. Given the definitions:
- Uploidy indicates a normal state, not a change.
- Parthenogenesis does not relate to chromosome number changes.
- Therefore, the correct answer is **Aneuploidy**.

4. **Conclusion**:
- The fractional change in the number of chromosomes is called **Aneuploidy**.