Viruses are not considered living because they:

• A. are able to reproduce without a host cell
• B. contain both DNA and RNA in the same particle
• C. cannot carry out metabolic processes independently
• D. have a cell wall but lack a nucleus

Answer: (C)

Verified step by step guidance

1. Understand the characteristics that define living organisms, such as the ability to carry out metabolic processes, reproduce independently, respond to stimuli, and maintain homeostasis.
2. Analyze each option given in the problem to see if it aligns with the criteria for living organisms:
3. - 'Are able to reproduce without a host cell': Viruses cannot reproduce without a host cell, so this statement is false for viruses.
4. - 'Contain both DNA and RNA in the same particle': Viruses typically contain either DNA or RNA, but not both simultaneously, so this is incorrect.
5. - 'Cannot carry out metabolic processes independently': Viruses lack the cellular machinery to perform metabolism on their own, which is a key reason they are not considered living.