Which of the following does not occur during interphase?

$A$: $DNA$ replication occurs only once in meiosis.
$R$: Exchange of $DNA$ in chromosomes is seen in mitosis.

When radioactive thymine is added to the medium during the synthesis of new $DNA$ in human cells,which of the following chromatids will become radioactive in cells that enter the phase immediately upon contact with radioactive thymine?

Which processes are induced during the cell cycle?

Select the incorrect statement from the following.

Compare the statements $A$ and $B$.
$Statement A$: Synthesis of $DNA$ takes place in the $S$-phase of interphase.
$Statement B$: Every chromosome,during metaphase,has two chromatids.
Choose the correct description.