Answer:
Red blood cell is microscopic structure
Mercury atom is particulate
Liquid mercury is macroscopic
Step-by-step explanation:
The three levels of organization is microscopic, macroscopic and particulate. The substances that can be seen by naked eyes is Macroscopic structures.
Example: Liquid mercury as it can be seen through naked eyes.
A mercury atom is a particulate matter which has not been sees by eyes or it can only be seen by electron microscope.
Red blood cells are very tiny and can be seen only in microscope.