Question

which microscope did anton van leeuwenhoek use to observe single - celled organisms?
simple microscope
compound light microscope
electron microscope
tunneling microscope

Explanation:

Anton van Leeuwenhoek is known for using a simple microscope. A simple microscope has a single lens. He made significant contributions to microbiology by observing single - celled organisms with his simple microscope. Compound light microscopes (with multiple lenses) were developed later. Electron microscopes (using electrons instead of light) and tunneling microscopes (based on quantum tunneling) are much more modern inventions.

Answer:

simple microscope