In meiosis-$I$,condensation and coiling of chromatin fibres started during

During which process does the genetic material replicate once,but the cell divides twice?

At which stage does the number of homologous chromosomes become halved?

During meiosis $I$,the chromosomes start pairing at

Match the stages of meiosis in Column $I$ to their characteristic features in Column $II$ and select the correct option using the codes given below.

Column $I$	Column $II$
$A$. Diakinesis	$1$. Crossing over takes place
$B$. Pachytene	$2$. Terminalisation of chiasmata
$C$. Zygotene	$3$. Chromosomes align at equatorial plate
$D$. Metaphase	$4$. Pairing of homologous chromosomes

Codes:
$A \quad B \quad C \quad D$

During the first meiotic division, the exchange of genetic material between the chromatids of homologous chromosomes occurs. What is this process called?