Question

which correctly describes crossing over?
the process whereby non - sister chromatids exchange genetic material
the process whereby homologous chromosomes are pulled to opposite poles of the cell
the process whereby sister chromatids are pulled to opposite poles of the cell
the process whereby homologous chromosome pairs align randomly along the metaphase plate

Explanation:

• Crossing over occurs during meiosis I. Non - sister chromatids (from homologous chromosomes) exchange genetic material.
• The process of homologous chromosomes being pulled to opposite poles is anaphase I of meiosis (not crossing over).
• Sister chromatids being pulled to opposite poles is anaphase II (mitosis or meiosis II).
• Homologous chromosome pairs aligning randomly along the metaphase plate is independent assortment (metaphase I).

Answer:

the process whereby non - sister chromatids exchange genetic material