Pyrimidine bases present in DNA are__________.

Pyrimidines bases:

1. Pyrimidines are reactive nitrogen heterocycles that have a close similarity to benzene but include two nitrogen atoms at the 1 and 3 places of the ring.
2. Pyrimidines, like purines, serve as RNA's informative monomers.

Cytosine:

1. Cytosine has the chemical formula C₄H₅N₃O.
2. It is a pyrimidine nucleobase.
3. Pyrimidine is a heterocyclic aromatic chemical molecule having a single pyrimidine ring that contains both nitrogen and carbon atoms.

Thymine:

1. Thymine has the chemical formula C₅H₆N₂O₂ and is a pyrimidine nucleobase.
2. Pyrimidine is a heterocyclic aromatic chemical molecule with a single pyrimidine ring that contains consecutive carbon and nitrogen atoms.

Final Answer:

Pyrimidine bases present in DNA are cytosine and thymine.