Which of the following is a true statement about viruses?

• A. Viruses can carry out metabolic processes independently.
• B. Viruses contain both DNA and RNA in all cases.
• C. Viruses are classified as prokaryotic organisms.
• D. Viruses require a host cell to reproduce.

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the nature of viruses. Viruses are unique infectious agents that cannot carry out metabolic processes on their own and must rely on a host cell for replication.
2. Step 2: Analyze the statement 'Viruses can carry out metabolic processes independently.' This is false because viruses lack the cellular machinery needed for metabolism and energy production.
3. Step 3: Consider the statement 'Viruses contain both DNA and RNA in all cases.' This is incorrect since viruses contain either DNA or RNA as their genetic material, but never both simultaneously.
4. Step 4: Evaluate the statement 'Viruses are classified as prokaryotic organisms.' This is false because viruses are not classified as living cells and do not fit into the domains of life such as prokaryotes or eukaryotes.
5. Step 5: Confirm that the true statement is 'Viruses require a host cell to reproduce,' which accurately reflects the obligate intracellular parasitic nature of viruses.