DNA consists of two polynucleotide chains, Each chain forms a right-handed spiral with how many bases in one turn of spiral?

Step-by-step solution

Watson and Crick proposed that DNA molecule is in the form of a double helix with two polynucleotide chains coiled around one another in a spiral. This is known as B-DNA or biological DNA. It has 10 nucleotides pairs per turn of the double helix and is right handed with a diameter of (20 Å ). One complete turn of the double helix is (34 Å ). The distance between adjacent stacks or nucleotides is (3.4 Å ). Hence, option (d) is correct.