Simplify the following text for a Grade 10 native English-speaking person.
Original: This nucleic acid is usually single-stranded RNA ( ssRNA ) but may be double-stranded RNA ( dsRNA ) . The ICTV classifies RNA viruses as those that belong to Group III , Group IV or Group V of the Baltimore classification system of classifying viruses , and does not consider viruses with DNA intermediates as RNA viruses .
Simplified: RNA viruses are viruses that use RNA as their genetic material .