ANATOMY

Detailed explanation-1: -Uracil is present only in RNA, whereas thymine is present only in DNA. Thus, thymine is the nitrogenous base which is not present in RNA.

Detailed explanation-2: -DNA contains four bases which are adenine (A), guanine (G), cytosine (C) and thymine (T). RNA also contains four bases, the first three bases are same as in DNA but the fourth one is uracil (U).

Detailed explanation-3: -RNA contains which of the following sets of nitrogenous bases? Explanation: Thymine is exclusively present in DNA. Uracil replaces thymine in RNA; thus, RNA contains the following four nitrogenous bases: adenine, guanine, cytosine, and uracil.

Detailed explanation-4: -Because thymine has a higher resistance to photochemical mutation and makes the genetic code more durable, DNA uses it instead of uracil.

Detailed explanation-5: -⇒ Thymine is present in DNA but not in RNA.