Trisomic conditions are

Options

A. n-1
B. 2n+1
C. 2n+2
D. 2n-2

Answer

### Step-by-Step Solution for the Question: Trisomic Conditions

1. **Understanding Chromosome Numbers**:
- Humans typically have 46 chromosomes, which are organized into 23 pairs. Each pair consists of one chromosome from the mother and one from the father. This is referred to as the diploid state (2n), where n is the number of unique chromosomes (23 in humans).

2. **Defining Haploid and Diploid**:
- The haploid state (n) refers to the number of chromosomes in germ cells (sperm and egg), which is half the diploid number. In humans, this is 23 chromosomes.

3. **Understanding Trisomy**:
- Trisomy occurs when there is an extra chromosome present in a pair. Instead of the normal two copies of a chromosome (2n), there are three copies (2n + 1). This condition arises due to a process called nondisjunction.

4. **Nondisjunction Explained**:
- Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division (anaphase). This can lead to gametes with an abnormal number of chromosomes.

5. **Examples of Trisomy**:
- A well-known example of trisomy is Down syndrome, which is caused by having three copies of chromosome 21. This condition can be denoted as trisomy 21.

6. **Conclusion**:
- Therefore, the trisomic condition can be summarized as having three copies of a particular chromosome instead of the usual two. In terms of notation, this is represented as 2n + 1.

### Final Answer:
Trisomic conditions are characterized by having three copies of a chromosome instead of the normal two, represented as 2n + 1.

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