What is a kinetochore?

$A$ : Golgi bodies and $ER$ disappear in early prophase.
$R$ : Their reorganisation stage is anaphase.

Select the correct match for $X$ and $Y$:

Column $X$	Column $Y$
$(1)$ Tetrad	$(P)$ Zygotene stage
$(2)$ Chiasmata	$(Q)$ Diplotene stage
$(3)$ Splitting of centromere	$(R)$ Meiosis
$(4)$ Bivalent	$(S)$ Pachytene stage
	$(T)$ Anaphase
	$(U)$ 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?

Distinguish between the anaphase of mitosis and the anaphase $I$ of meiosis.

Select the correct option for the following matches:

List-$I$	List-$II$
$(1)$ Metaphase-$I$	$(a)$ Number of chromosomes becomes half of the parent cell
$(2)$ Anaphase-$I$	$(b)$ Each chromosome splits at the centromere to form chromatids
$(3)$ Anaphase-$II$	$(c)$ Homologous chromosomes form pairs at the equatorial plate
$(4)$ Telophase-$II$	$(d)$ Homologous chromosomes move towards opposite poles