The nucleus is enclosed in:

Which of the following is not a membrane-bound organelle?

The eukaryotic chromosomes are made up of

In which structure is the 'beads-on-a-string' appearance observed?

The nucleolus is formed by . . . . . . .

Read the following statements $:-$
$(i)$ Centromere is present in the middle of the chromosomes and forms two equal arms.
$(ii)$ Chromosome has a terminal centromere.
$(iii)$ Centromere lies close to the end of the chromosome forming one extremely short and one very long arm.
$(iv)$ Centromere lies slightly away from the middle of the chromosome resulting in one shorter arm and one longer arm.
Select the correct option as per the codes given below $:-$