In which stage does the chromatin network condense into chromosomes?

If you are provided with root tips of an onion and are asked to count the chromosomes,which stage of mitosis would you look for?

From which of the following do spindle fibers originate?

The nuclear spindle consists of

In which phase do new nuclei come into existence?

$A$ student was asked to identify a permanent slide of mitosis. He made the following observations:
$(i)$ Splitting of centromere and formation of daughter chromatids.
(ii) Chromatids are migrating towards the opposite poles.
The stage would be