Question

Given below are groups of terms. In each group the first pair indicates the relationship between the two terms. Rewrite and complete the second pair on a similar basis.
Example : Oxygen : Inspiration : : Carbon dioxide : Expiration
Adenine : Thymine : : Cytosine : __________.

Answer 1

Nitrogenous bases are nitrogen-containing compounds that form nucleosides, which in turn are components of nucleotides, which are basic building blocks of nucleic acids. Each DNA molecule consists of four nitrogen containing nucleobases: Adenine (A), Cytosine (C), Guanine (G) and thymine (T).

Adenine can form two hydrogen bonds with thymine and cytosine can form three hydrogen bonds with guanine. A bonds only with T and C bonds only with G. Because of complementary base pairing, the hydrogen-bonded nitrogenous bases are often referred to as base pairs.

So, the answer is- Adenine : Thymine :: Cytosine : Guanine