Can you directly observe microorganisms on your hand with the naked eye?

• A. No, most microorganisms are too small to be seen without a microscope.
• B. Yes, all microorganisms are visible to the naked eye.
• C. Only viruses can be seen without magnification.
• D. Microorganisms on the skin are visible only under ultraviolet light.

Answer: (A)

Verified step by step guidance

1. Understand the size range of microorganisms: Most microorganisms, such as bacteria and viruses, are extremely small, typically measured in micrometers (\(\mu m\)) or nanometers (nm), which is far below the resolution limit of the human eye.
2. Recall the resolution limit of the human eye: The human eye can generally resolve objects down to about 0.1 millimeters (100 micrometers), so anything smaller than this cannot be seen clearly without magnification.
3. Consider the types of microorganisms: Bacteria and most fungi are microscopic and require a microscope to be seen. Viruses are even smaller and cannot be seen with a light microscope, let alone the naked eye.
4. Evaluate the options given: Since microorganisms are smaller than the resolution limit of the naked eye, they cannot be directly observed without magnification, making the statement 'No, most microorganisms are too small to be seen without a microscope' correct.
5. Understand that ultraviolet light can help visualize some microorganisms indirectly (e.g., through fluorescence), but it does not make them visible to the naked eye without special equipment.