Assertion : The nitrogen bases of the two chains of DNA are held together by hydrogen bonds.
Reason : Both chains of DNA are anitparallel.

Options

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion.
B. If both the assertion and reason are true but the reason is not a correct explanation of the assetion
C. If the assertion is true but the reason is false
D. If the both the assertion and reason are false

Answer

b

Explanation

b) The nitrogen bases of DNA are of two types namely(i) pyrimidines and (ii) purines. The nitrogen bases of the two chains formed complementary paris with purine of one and pyrimidine of the other held together by hydrogen bonds. The two chains are antiparallel with `5^(')to3^(')` orientation of one and `3^(')to5^(')` orientation of the other.