Final answer:
Viroids are composed of single-stranded RNA (ssRNA) and are much simpler than viruses, reproducing only within a host cell and not producing any proteins.
Step-by-step explanation:
Viroids are characteristically composed of single-stranded RNA (ssRNA). Unlike viruses that may contain various types of genetic materials such as ssDNA, dsDNA, or dsRNA, viroids consist of a much simpler structure. Specifically, viroids are plant pathogens that consist of small, single-stranded, circular RNA particles. They do not have a capsid or outer envelope, and they can reproduce only within a host cell. Moreover, viroids do not manufacture any proteins and only produce a single, specific RNA molecule. It's important to note that viroids affect only plants, and human diseases caused by viroids have yet to be identified.So, in response to the question, the correct answer is A) ssRNA.