What tool is used for viewing very small objects like bacteria?

The correct choice is a microscope, which is specifically designed to view objects that are too small for the naked eye to see, such as bacteria, cells, and other microscopic entities. Microscopes use lenses to magnify small objects, allowing for detailed observation and analysis. They can achieve much higher magnifications compared to other tools, making them essential in scientific fields like microbiology and histology.

In contrast, an endoscope is a tool used primarily for examining internal organs and cavities in the body rather than for viewing tiny specimens like bacteria. A magnifying glass, while useful for enlarging small objects, does not provide the level of detail or magnification that a microscope offers. A telescope is designed for viewing distant celestial objects, such as stars and planets, and is not suitable for observing small, close-up objects.