It is not true about viruses:

Explanation

Viruses cannot have both DNA and RNA as their genome because each type requires a completely different replication strategy and enzymes. DNA viruses depend on DNA polymerases, while RNA viruses use RNA-dependent RNA polymerases, and these systems are not compatible within a single genome. Carrying both would be inefficient and unstable, so viruses are classified strictly as either DNA or RNA viruses, never both.