A)Meiosis involves two rounds of DNA replication followed by a single cell division.
B)Meiosis involves a single round of DNA replication followed by four successive cell divisions.
C)Meiosis involves four rounds of DNA replication followed by two successive cell divisions.
D)Meiosis involves a single round of DNA replication followed by two successive cell divisions.

A)sister chromatids segregating inappropriately
B)nonsister chromatids segregating inappropriately
C)a reciprocal rearrangement of parts between nonhomologous chromosomes (for example, the left arm of Chromosome 2 exchanging places with the right arm of Chromosome 3)
D)an extra set of chromosomes produced during S phase (for example, if paternal Chromosome 3 were replicated twice)

A)sister chromatids undergo crossing-over with each other.
B)chiasmata hold chromosomes together.
C)one crossover event occurs for each pair of human chromosomes.
D)the synaptonemal complex keeps the sister chromatids together until anaphase II.