Multiple choice

Non sister chromatids in each bivalent exchange their segments during pachytene. This is called ____.

  1. tetrads

  2. crossing over

  3. synapsis

  4. diplotene

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Crossing over is the exchange of genetic material between non-sister chromatids of homologous chromosomes during meiosis. This occurs during pachytene stage of prophase I and increases genetic variation. Tetrads refer to the four chromatids together, not the exchange process itself.