Answer: capsid.
- A capsid
- B cell wall
- C plasma membrane
- D nucleoid
Correct answer: A. capsid
Explanation: The capsid is the protective protein coat of a virus.
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.