Metaphase is the best stage to count the number and study the morphology of chromosomes.

Explanation:
During the cell cycle, chromosomes undergo various stages, including prophase, metaphase, anaphase, and telophase. Each of these stages has distinct characteristics and functions. However, when it comes to counting the number and studying the morphology of chromosomes, the metaphase stage is considered the most suitable.

What is Metaphase?
Metaphase is the stage of mitosis or meiosis where the chromosomes are maximally condensed and aligned along the equatorial plane of the cell. During metaphase, the nuclear envelope disintegrates, and the spindle fibers attach to the centromeres of the chromosomes. This alignment of chromosomes at the center of the cell is crucial for accurate distribution of genetic material during cell division.

Why is Metaphase the best stage?
There are several reasons why metaphase is the most suitable stage for counting the number and studying the morphology of chromosomes:

1. Visible and condensed chromosomes: During metaphase, the chromosomes are highly condensed, making them more visible and distinguishable under a microscope. This condensation facilitates the study of their morphology and structural details.

2. Aligned and organized arrangement: In metaphase, the chromosomes align themselves along the metaphase plate, which is the equatorial plane of the cell. This alignment allows for a clear and organized arrangement of chromosomes, making it easier to count and study their number.

3. Minimal overlapping: The alignment of chromosomes in metaphase minimizes overlapping, ensuring that each chromosome is visible and can be studied individually. This is important for accurate chromosome counting and analysis.

4. Stable and static stage: Unlike other stages of cell division, metaphase is relatively stable and static. This allows researchers to capture clear images and observe the chromosomes without the added challenge of movement or dynamic changes.

5. High mitotic index: Metaphase is the stage where most cells in a tissue or culture are likely to be found. This high mitotic index increases the chances of finding cells in metaphase, making it easier to study the chromosomes.

In conclusion, metaphase is considered the best stage to count the number and study the morphology of chromosomes due to the visible and condensed chromosomes, aligned arrangement, minimal overlapping, stability, and high mitotic index.