All of the following are characteristics of viruses except:

• A. They contain either DNA or RNA as genetic material
• B. They reproduce by binary fission
• C. They lack cellular structures such as ribosomes
• D. They are obligate intracellular parasites

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the nature of viruses by reviewing their basic characteristics. Viruses are unique infectious agents that differ from cellular life forms.
2. Step 2: Recall that viruses contain either DNA or RNA as their genetic material, but never both simultaneously. This is a fundamental trait of viruses.
3. Step 3: Recognize that viruses lack cellular structures such as ribosomes, which are necessary for protein synthesis in cells. Instead, they rely on the host cell's machinery.
4. Step 4: Know that viruses are obligate intracellular parasites, meaning they must infect a host cell to reproduce because they cannot carry out metabolic processes on their own.
5. Step 5: Identify that viruses do not reproduce by binary fission, which is a method of asexual reproduction used by bacteria and some other single-celled organisms. Instead, viruses replicate by assembling new viral particles inside the host cell.