Final answer:
Viroids are small RNA particles that infect plants, causing crop failures and economic losses. They reproduce within a host cell and do not produce proteins. They have a specific RNA molecule.
Step-by-step explanation:
Viroids are small, single-stranded, circular RNA particles that infect plants. They do not have a capsid or outer envelope like viruses, but they can reproduce only within a host cell. Viroids do not produce proteins and they have a specific RNA molecule. They can infect crops such as potatoes, cucumbers, tomatoes, chrysanthemums, avocados, and coconut palms, causing crop failures and significant economic losses.