Exchange of segments between non -sister chromatids of homologous chromosomes is

Options

A. crossing over
B. transolation
C. linkage
D. inversion

Explanation

To solve the question regarding the exchange of segments between non-sister chromatids of homologous chromosomes, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terminology**:
- Non-sister chromatids refer to chromatids from homologous chromosomes. Homologous chromosomes are pairs of chromosomes (one from each parent) that have the same genes but may have different alleles.

2. **Identify the Process**:
- The exchange of segments between non-sister chromatids occurs during a specific phase of meiosis, which is a type of cell division that produces gametes (sperm and eggs).

3. **Recognize the Mechanism**:
- This exchange is known as "crossing over." During prophase I of meiosis, homologous chromosomes pair up and form structures called tetrads. While in this formation, segments of chromatids can break and reattach to the other chromatid.

4. **Conclusion**:
- The correct term for the exchange of segments between non-sister chromatids of homologous chromosomes is "crossing over."

5. **Evaluate the Options**:
- The question provides four options:
- a) Crossing over
- b) Translocation
- c) Linkage
- d) Inversion
- Based on our understanding, the correct answer is option (a) Crossing over.

### Final Answer:
The exchange of segments between non-sister chromatids of homologous chromosomes is called "crossing over."

---