Antonie van Leeuwenhoek was known for which discovery in late 17^th century?

Observation of bacteria and protozoa

The correct answer is Option (2) – Observation of bacteria and protozoa

Antonie van Leeuwenhoek, a Dutch scientist, is best known for his observation of bacteria and protozoa. In the late 17th century, he made significant contributions to the field of microbiology by using a simple microscope of his own design to discover and study microscopic life forms, including bacteria and protozoa. His meticulous observations opened up a new world of understanding about the existence of tiny living organisms that were previously unknown. Van Leeuwenhoek's work laid the foundation for the field of microbiology and greatly advanced our knowledge of the microbial world.