Instructions: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
Input: Viruses biological agents that infect living hosts contain dna, yet lack the other parts shared by all cells, including a plasma membrane, cytoplasm, and ribosomes.
Output:
What biological agents that infect living hosts contain dna, yet lack the other parts shared by all cells, including a plasma membrane, cytoplasm, and ribosomes?