When homologous chromosomes trade alleles, it's called crossing over.

Here's a breakdown:

* Homologous chromosomes: These are chromosome pairs that carry the same genes but may have different alleles (versions) of those genes.

* Alleles: These are alternative forms of a gene. For example, a gene for eye color might have an allele for brown eyes and an allele for blue eyes.

* Crossing over: This is the process during meiosis where homologous chromosomes exchange segments of DNA. This exchange results in new combinations of alleles on each chromosome, increasing genetic diversity.

Let me know if you have any other questions!