The nucleus is a ....... structure.

What do $a$ and $b$ represent in the given figure,respectively?

Which of the following is a membrane-less organelle?

$S -$ Assertion: Individual chromosomes are not identifiable during interphase.
$R -$ Reason: They exist as highly extended and elaborate nucleoprotein fibers called chromatin.

The centromere may also be called as:

$A$ chromosome having the centromere in its middle is called: