With which nitrogenous base does $Adenine$ pair?

Which is known as soluble $RNA$?

The coding sequences of genes are known as . . . . . . .

What background information did Watson and Crick have available for developing a model of $DNA$? What was their contribution?

What structure is formed when two polynucleotide chains in $DNA$ are coiled together?

One of the strands of double stranded $\text{DNA}$ has base composition as follows: $15 \% A, 15 \% T, 40 \% G$ and $30 \% C$. What will be the percentage of these bases in the complementary strand?