Question

Definition of adenine, guanine, cytosine, and thymine

Answer 1

Adenine, guanine, cytosine and thymine are all nitrogenous bases present in the DNA or RNA.
Adenine and guanine are purines whereas cytosine and thymine are pyrimidines.

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Answer 2

==)adenine a compound which is one of the four constituent bases of nucleic acids. A purine derivative, it is paired with thymine in double-stranded DNA
==)guanine a compound that occurs in guano and fish scales, and is one of the four constituent bases of nucleic acids. A pure derivative, it is paired with cytosine in double-stranded DNA.
==)cytosine a compound found in living tissue as a constituent base of DNA. It is paired with guanine in double-stranded DNA
==)thymine_____________???