Which bond provides stability to the helical structure of $DNA$?

The antiparallel strands in $DNA$ are the result of:

The telomeres of eukaryotic chromosomes consist of short sequences rich in:

Which of the following nitrogenous bases is not found in $DNA$?

Given below are two statements:
Statement $I$: In prokaryotes,the positively charged $DNA$ is held with some negatively charged proteins in a region called nucleoid.
Statement $II$: In eukaryotes,the negatively charged $DNA$ is wrapped around the positively charged histone octamer to form nucleosome.
In the light of the above statements,choose the correct answer from the options given below:

Which structure consists of two polynucleotide chains forming a helical structure?