Why are viruses often considered to be nonliving?

• A. They cannot carry out metabolic processes independently.
• B. They can reproduce on their own without a host cell.
• C. They are able to synthesize their own ATP.
• D. They are composed only of proteins and lack genetic material.

Answer: (A)

Verified step by step guidance

1. Understand the definition of living organisms: Living organisms typically carry out metabolic processes, grow, reproduce independently, and respond to their environment.
2. Analyze the characteristics of viruses: Viruses consist of genetic material (DNA or RNA) enclosed in a protein coat, but they lack cellular structures and metabolic machinery.
3. Consider the ability of viruses to reproduce: Viruses cannot reproduce on their own; they require a host cell to replicate their genetic material and produce new virus particles.
4. Evaluate metabolic activity: Viruses do not carry out metabolic processes such as energy production (e.g., ATP synthesis) independently; they rely entirely on the host cell's metabolism.
5. Conclude why viruses are considered nonliving: Because viruses cannot independently perform metabolic functions or reproduce without a host, they are often classified as nonliving entities.