The best stage to view structure, size and to count the number of chromosomes is

Options

A. Metaphase
B. Late prophase
C. Telophase
D. I-phase

Answer

**Step-by-Step Solution:**

1. **Understanding the Cell Cycle:** The cell cycle consists of two main phases: Interphase and M-phase (mitotic phase). Interphase is where the cell spends most of its time, while M-phase is where cell division occurs.

2. **Identifying M-phase Stages:** The M-phase is further divided into four stages: Prophase, Metaphase, Anaphase, and Telophase. Each of these stages has distinct characteristics.

3. **Focusing on Metaphase:** Among these stages, Metaphase is crucial for observing chromosomes. During this stage, chromosomes are fully condensed and align at the metaphase plate, making them easily visible under a microscope.

4. **Chromosome Visibility:** The complete condensation of chromosomes in Metaphase allows for clear visualization of their structure and size. This is the optimal time to count the number of chromosomes because they are distinct and not tangled.

5. **Comparing Other Stages:**
- **Late Prophase:** In this stage, chromosomes begin to condense, but they are not as clearly visible as in Metaphase. The nuclear envelope starts to break down, and other cellular structures are still present.
- **Telophase:** Here, chromosomes are at opposite poles and begin to de-condense, making them less distinct. The nuclear envelope reforms, and the cell is preparing to divide.
- **Interphase:** During Interphase, chromosomes are not visible as they are in a relaxed state (chromatin), making it impossible to count them.

6. **Conclusion:** Based on the characteristics of each stage, Metaphase is identified as the best stage to view the structure, size, and count the number of chromosomes.

**Final Answer:** The best stage to view the structure, size, and to count the number of chromosomes is **Metaphase**.

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