Q4. Assertion: no DNA replication takes place in interkinesis. Reason: each chromosome entering meiosis II still has two sister chromatids from the S phase before meiosis I. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion: the chromatids made in the single S phase are separated only in anaphase II (NCERT pages 125 and 127).
Q5. What marks the beginning of diplotene, and what marks diakinesis?
Diplotene begins with the dissolution of the synaptonemal complex; diakinesis is marked by terminalisation of chiasmata (NCERT page 126).
Q6. List three differences between mitosis and meiosis. (NCERT Exercise 11)
Mitosis has one division and gives two cells with the parent’s chromosome number; meiosis has two divisions and gives four haploid cells. Homologous chromosomes pair and cross over only in meiosis. In mitotic anaphase the centromeres split; in anaphase I they do not, and the homologues separate (NCERT pages 122–129).