The complex formed by a pair of synapsed homologous chromosomes is called

Options

A. Bivalent
B. Axoneme
C. Equatorial plate
D. Kinetochore

Answer

To solve the question, "The complex formed by a pair of synapsed homologous chromosomes is called," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context of the Question:**
- The question pertains to the process of meiosis, specifically focusing on the behavior of chromosomes during this process.

2. **Identify Key Terms:**
- The terms "synapsed homologous chromosomes" are crucial. Synapsis refers to the pairing of homologous chromosomes during meiosis.

3. **Recall the Stages of Meiosis:**
- Meiosis consists of two main stages: Meiosis I and Meiosis II. The question is specifically about Meiosis I.

4. **Focus on Prophase I:**
- During Meiosis I, the first phase is Prophase I, which is further divided into several stages, including leptotene, zygotene, pachytene, diplotene, and diakinesis.

5. **Identify the Relevant Stage:**
- The stage where homologous chromosomes pair up is called the zygotene stage. However, the formation of the complex is specifically noted during the pachytene stage.

6. **Define the Complex:**
- During the pachytene stage, the paired homologous chromosomes form a structure known as a "bivalent."

7. **Conclusion:**
- Therefore, the answer to the question is that the complex formed by a pair of synapsed homologous chromosomes is called a **bivalent**.

### Final Answer:
The complex formed by a pair of synapsed homologous chromosomes is called a **bivalent**.

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