How are viroids like viruses?

Both are acellular particles composed of generic material.

Explanation:

Viruses are infectious acellular particles of DNA or RNA packed in a capsid composed of proteins and lipids. Viruses are not cells and can't reproduce of their own needing host cells for its reproduction. Virions are very similar to virus, but virions are more simple particles than viruses. Virions are an acellular particle composed of a naked shot strand of circular, single-stranded of RNA that don't codify proteins, it only replicate the RNA. Virions cause damage to the host cell by interfering in the generic regulation of the host cell.

To sum up, virions and viruses are similar in structure, the difference lies in the complexity of the particle, being viroids more simple than viruses.