Through which method of cell division are the diploid chromosomes divided into haploid gametes?

The correct option is Meiosis.

Cell division is a fundamental biological process by which a parent cell divides into two or more daughter cells. Depending on the purpose of division and the type of cell involved, cell division occurs primarily through two main pathways: mitosis and meiosis.

1. Understanding Diploid and Haploid Cells:
Somatic (body) cells are typically diploid, represented as:

$2n$

This means they contain two complete sets of chromosomes (one set inherited from each parent). On the other hand, sex cells or gametes (such as sperm and egg cells) are haploid, represented as:

$n$

Haploid cells contain only a single set of chromosomes so that during fertilization, the combination of two haploid gametes restores the diploid chromosome number ($n+n=2n$) in the offspring.

2. Why Meiosis is the Correct Method:
Meiosis is a specialized type of cell division that reduces the chromosome number by half. It consists of two sequential divisions: Meiosis I and Meiosis II. Through these divisions, one diploid parent cell produces four genetically distinct haploid gametes.

3. Analysis of Other Options:
• Mitosis: This is an equational division process used for growth and tissue repair, resulting in two daughter cells that are genetically identical to the parent cell and maintain the same diploid ($2n$) chromosome number.
• Binary Fission: A method of asexual reproduction primarily seen in prokaryotes (like bacteria) where a single cell splits into two equal parts.
• Amitosis: A simple form of direct nuclear division without chromosome formation or spindle apparatus, commonly seen in unicellular organisms or specialized cells.

Therefore, diploid chromosomes are divided into haploid gametes specifically through the process of Meiosis.