Question

which statements describe crossing over?
□ increases genetic variation across gametes
□ occurs between homologous chromosomes
□ separates chromosome pairs into gametes
□ occurs between duplicated sister chromatids

Explanation:

• Increases genetic variation across gametes: Crossing - over leads to new combinations of alleles on chromosomes, which are then passed on to gametes, increasing genetic diversity.
• Occurs between homologous chromosomes: During meiosis, crossing - over specifically takes place between homologous chromosomes (not sister chromatids). Homologous chromosomes pair up, and segments of their chromatids are exchanged.
• Separates chromosome pairs into gametes: This is the process of independent assortment (in meiosis I) or simply the separation of chromosomes during meiosis, not crossing - over.
• Occurs between duplicated sister chromatids: Crossing - over occurs between non - sister chromatids of homologous chromosomes. Sister chromatids are identical (except for mutations) and crossing - over between them would not create new genetic combinations.

Answer:

• increases genetic variation across gametes
• occurs between homologous chromosomes