Question

what process occurs when chromosomes are in a tetrad of sister chromatids? the chromosomes combine into one long strand for fertilization. the chromosomes exchange portions of their dna through crossing over. all the genetic information is destroyed, so it does not mix in the dna.

Explanation:

In meiosis, when chromosomes are in a tetrad of sister - chromatids, the process of crossing - over occurs. During crossing - over, homologous chromosomes exchange segments of DNA, which increases genetic diversity. The other options are incorrect as chromosomes do not combine into one long strand for fertilization in this way, and genetic information is not destroyed.

Answer:

The chromosomes exchange portions of their DNA through crossing over.