Question

which type of microscope was the first to be used for studying single - celled organisms? simple microscope tunneling microscope compound light microscope electron microscope

Explanation:

Antonie van Leeuwenhoek used a simple microscope in the 17th century to observe single - celled organisms. Tunneling microscopes (developed much later) are for different purposes (e.g., observing surfaces at the atomic scale). Compound light microscopes came after simple microscopes in terms of the timeline of observing single - celled organisms. Electron microscopes are also a later development (20th century) and have different working principles.

Answer:

simple microscope