The condition in which the number of chromosomes changes in multiples of the genome is

Options

A. Polyploidy
B. Trisomy
C. Monosomy
D. Nullisomy

Answer

To solve the question regarding the condition in which the number of chromosomes changes in multiples of the genome, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about a specific condition related to the number of chromosomes in an organism. We need to identify the term that describes a change in chromosome number in multiples of the genome.

2. **Identifying Key Terms**:
- **Genome**: The complete set of genes or genetic material present in a cell or organism.
- **Chromosome Number**: The total number of chromosomes in a cell.

3. **Analyzing the Options**:
- **Option 1: Polyploidy**: This refers to a condition where an organism has more than two complete sets of chromosomes (e.g., triploid, tetraploid). This is a change in chromosome number in multiples of the genome.
- **Option 2: Trisomy**: This condition involves having three copies of a particular chromosome instead of the normal two. This is not a multiple of the entire genome.
- **Option 3: Monosomy**: This is the presence of only one chromosome from a pair, which is also not a multiple.
- **Option 4: Nullizomy**: This condition involves the absence of both chromosomes of a pair, which again does not fit the definition of multiples of the genome.

4. **Conclusion**: Based on the analysis, the correct answer is **Option 1: Polyploidy**. This condition is characterized by an increase in the number of chromosome sets, making it a change in multiples of the genome.

### Final Answer:
The condition in which the number of chromosomes changes in multiples of the genome is **Polyploidy**.

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