Which statement about RNA is not true? Uracil is found in RNA as one of the two pyrimidine nitrogenous bases. RNA possesses catalytic activity, which earned it the name "ribozyme." RNA is thought to have dominated early life on earth, serving as both genetic information and as a catalyst. RNA is a more stable molecule than DNA. RNA typically consists of a single polynucleotide strand with distinct secondary structures.

RNA is a more stable molecule than DNA

Explanation: DNA (deoxyribonucleic acid) is much stable than RNA (ribonucleic acid) for many reasons; Frist of all its because of the double strand of the DNA versus the single-stranded RNA. This is thanks to the Hydrogen bonding between bases since those bondings release free energy that allows the molecule to be provided by more thermodynamic stability.

Also the lack of 2′ OH groups makes DNA more stable since the OH groups are very reactive by themselves. In the DNA sugar molecule there is not a spare OH group that could start reacting on its own. So this is why DNA is immune to chemical reactions, while RNA (having an extra OH group) is more chemically "promiscuous".