Which correctly describes crossing over?
the process whereby nonsister chromatids exchange genetic material
the process whereby homologous chromosomes are pulled to opposite poles of the cell
the process whereby sister chromatids are pulled to opposite poles of the cell
the process whereby homologous chromosome pairs align randomly along the metaphase plate

Crossing-over is a unique phenomenon which occurs only in the prophase I stage of meiotic division i.e. meiosis I. It is the process whereby nonsister chromatids of homologous chromosomes (similar but non-identical chromosomes from male and female parents) exchange their genetic material.

This exchange between nonsister chromatids aids in genetic variation among species that reproduce sexually via meiosis. Hence, meiosis, which is peculiar to sexually-reproducing organisms is the only way that promotes genetic variation in species.

Oseni Oseni · Answer 2 · 2021-10-08T18:54:31+02:00

The option that correctly describes crossing over is the one that says that it is a process whereby non-sister chromatids exchange genetic materials.

Crossing over is a process that happens during the early stages of meiosis, meiosis I to be precise. Meiosis itself is a cell division involving the sex or germline cells.

During the early stages of meiosis, genetic materials in the cell thicken to form threads. Then, homologous chromosomes start pairing up by forming a complex known as the synaptonemal complex.

After the pairing up of homologous chromosomes, tetrads or bivalents, result. Thereafter, non-sister chromatids exchange chromosomal segments in a process known as crossing over.

The crossing over is evidenced by the presence of an X-shaped figure, otherwise known as chiasmata, along the synapsed chromosomes.

More about crossing over can be found here: https://brainly.com/question/394891