Question

which of the following best describes crossing over? choose 1 answer: a crossing over is the process by which male and female gametes exchange chromosomes during fertilization. b crossing over is the process by which sister chromatids exchange segments with each other during meiosis. c crossing over is the process by which paired homologous chromosomes swap sections during meiosis.

Explanation:

• Option A: Fertilization is the fusion of gametes, not where crossing over occurs. Crossing over is during meiosis, not fertilization, so A is incorrect.
• Option B: Sister chromatids are identical (except for mutations) and do not exchange segments during crossing over. Crossing over is between homologous chromosomes, not sister chromatids, so B is incorrect.
• Option C: Crossing over occurs during meiosis I, specifically between paired homologous chromosomes (non - sister chromatids), where they swap sections of genetic material. This increases genetic variation. So C correctly describes crossing over.

Answer:

C. Crossing over is the process by which paired homologous chromosomes swap sections during meiosis.