In meiosis, recombination
a. during both prophases i and ii and involves exchange of chromosome fragments between sister chromatids.
b. during both prophases i and ii and involves exchange of chromosome fragments between all four chromatids.
c. during only prophase ii and involves exchange of chromosome fragments between sister chromatids.
d. during only prophase i and involves exchange between chromatids of homologous chromosomes.

d.during only prophase I and involves exchange between chromatids of homologous chromosomes.

Explanation:

Crossing over is the event that occurs during the pachytene stage of prophase I of meiosis I and results in the formation of new gene combinations, that is, recombination. During pachytene of prophase I, the synapsed homologous chromosomes exchange the genetic segments between them.

To facilitate recombination, synaptonemal complex assists in pairing the homologous chromosomes together during the zygotene stage of prophase I. Zygotene is followed by pachytene. A cut in two non-sister chromatids of a homologous pair, exchange of the broken segments followed by ligation results in recombination. Prophase II does not include crossing over.

the answer is otpion c) understanding

he wants to be heard one more time. he wants to be understood. he needs the truth one more time.

small, big, or no change could occur in the phenotype. it could cause something as simple as a cats ears to curl backwards or something as frighting as death. it could also occur in the protien-coding area and have an effect on that but no effect on the amino acids. what has to occur is a changing in the hox gene or the control gene.