Problem:
Question: When does recombination occur?
a. at the two-strand stage, before DNA replication and when each member of a homologous chromosome pair is composed of two sister chromatids.
b. at the two-strand stage, after DNA replication, when the sister chromatids have been separated.
c. at the four-strand stage, before DNA replication, when each member of a homologous chromosome pair is composed of two sister chromatids.
d. before DNA replication.
e. at the four-strand stage, after DNA replication, when each member of a homologous chromosome pair is composed of two sister chromatids.
Give reasoning with your answer.