Who coined the term $chromatin$?

Depending upon size and centromere position,the $46$ chromosomes have been divided into a number of groups.

Which of the following regulates and governs the physiological processes of the cell?

The genomic content of the nucleus is constant for a given species,whereas the extrachromosomal $DNA$ is found to be variable among the members of a population. Explain.

The centromere may also be called as:

Which of the following statements is/are correct?
$(a)$ The nuclear matrix or nucleoplasm contains the nucleolus and chromatin.
$(b)$ The outer nuclear membrane $(Ectokaryotheca)$ is usually continuous with the endoplasmic reticulum and also bears ribosomes on it.
$(c)$ Cells that are actively synthesizing protein have small and fewer nucleoli.