Answer: Single-stranded RNA.
- A Single-stranded RNA
- B Double-stranded DNA mainly
- C Double-stranded RNA mainly
- D Usually both DNA and RNA
Correct answer: A. Single-stranded RNA
Explanation: Most viruses infecting plants have single-stranded RNA as genetic material. Animal viruses may have single or double-stranded RNA, or double-stranded DNA.
Whittaker's five-kingdom system (1969) groups all cellular life by cell structure and nutrition; viruses, viroids, and lichens fall outside this system entirely since they aren't independently classifiable as one of the five.
Concept context
Whittaker's five kingdom system covering Monera, Protista, Fungi, plus viruses, viroids, and lichens. A foundational NEET chapter on how living organisms are grouped.