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

Options

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

Answer

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

### Step-by-Step Solution:

1. **Understand the Terms**:
- First, we need to understand what is meant by "synapsed homologous chromosomes." Synapsis is the process during which homologous chromosomes pair up during meiosis.

2. **Identify the Stage in Meiosis**:
- The pairing of homologous chromosomes occurs during prophase 1 of meiosis. This is a crucial stage where genetic recombination can occur.

3. **Define the Complex**:
- The term used to describe the complex formed by a pair of synapsed homologous chromosomes is "bivalent." This term specifically refers to the structure that consists of two homologous chromosomes that are closely aligned.

4. **Clarify the Context**:
- The bivalent structure is particularly relevant during the zygotene and pachytene stages of prophase 1 in meiosis, where homologous chromosomes are fully synapsed.

5. **Evaluate Other Options**:
- Option B (axoneme) refers to the structural component of cilia and flagella, not related to chromosomes.
- Option C (equatorial plate) describes the arrangement of chromosomes during metaphase, not the pairing of homologous chromosomes.
- Option D (kinetochore) is a protein complex associated with the centromere of chromosomes, which is also not relevant to the synapsis of homologous chromosomes.

6. **Conclude the Answer**:
- Based on the definitions and context, the correct answer is **Option A: bivalent**.

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

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