Final answer:
Crossing over occurs during meiosis I and is responsible for recombination, increasing genetic variation. It does not occur during meiosis II. Hence the correct answer is option B
Step-by-step explanation:
False. Crossing over occurs during meiosis I and is responsible for recombination. It is the process where homologous chromosomes pair up and exchange segments of genetic material. This recombination creates unique combinations of genes, increasing genetic variation. During meiosis II, the recombinant chromosomes go on to separate, resulting in daughter cells with different sets of alleles and genes than their parents.