Final answer:
Chromosomes form from homologous chromosomes binding to create tetrads during prophase I. They ensure genetic diversity through independent assortment and each cell receiving an identical set of chromosomes during cell division.
Step-by-step explanation:
Chromosomes are the structures that DNA condenses into to ensure each new cell receives a complete set of genetic material during cell division. Homologous chromosomes bind firmly together along their lengths, forming a tetrad during prophase I of meiosis. These tetrads line up at the metaphase plate midway between the two poles of the cell, and the orientation of each tetrad is independent of the others. This setup assures that cells inherit a mix of maternal and paternal chromosomes leading to genetic variation.
The randomness in the orientation of tetrads during metaphase I leads to a process called independent assortment, further contributing to genetic diversity. In humans, one set of 23 chromosomes comes from the mother, and the other set comes from the father, totaling 46 chromosomes. Each chromosome consists of two sister chromatids joined at a centromere, and during cell division, they ensure that each new cell contains identical DNA.