This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Most common physiological form of DNA 
Select and explain. 
A. A-form, B. B-form, C. Z-form, D. C-form
B: B-form
Answer: B: B-form 
Explanation: DNA can exist in at least six forms, i.e. A, B, C, D, E and Z.The B-form of DNA is the most common form of DNA and is right-handed helix.It is the strandard DNA structure with 10 base pairs per turn.Watson and Crick model describes the B-form of DNA.Other forms of DNA are A-form (contains 11 base pairs per turn and is right handed helix) and Z-form (contains 12 base pairs per turn and is left handed helix).Z-form is ored by alternating G-C sequences in alcohol and high salt solution; and is inhibited by alternating A-T sequnces (Note-B form has minimum base pairs per turn, i.e. 10).