In $DNA$,cytosine pairs with

In $DNA$ molecule,which of the following base pair is present?

What is required for the packaging of chromatin at a higher level?

Adjacent nucleotides in a polynucleotide chain are joined by

How many nucleotides are present in one turn of $DNA$ helix (in $pairs$)?

Assertion : $DNA$ is associated with proteins.
Reason : $DNA$ binds around histone proteins that form a pool and the entire structure is called a nucleosome.