What is formed when a deoxyribose sugar combines with a nitrogenous base?

What is the similarity between $DNA$ and $RNA$?

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

In a $DNA$ molecule,if the base ratio $(A+T)/(G+C)$ is $0.3$ and the amount of $A+T$ nitrogenous bases is $30,000$,what will be the amount of $G+C$ nitrogenous bases in the $DNA$ (in $,000$)?

Which nitrogenous base is $NOT$ present in the structure of $DNA$?

What is the pitch of one turn of the $DNA$ helix?