Question

1. what did anton van leeuwenhoek observe using early microscopes?

a. living microorganisms
b. plant tissues
c. cork cells
d. viruses

Explanation:

Anton van Leeuwenhoek is known for observing living microorganisms (like bacteria, protozoa) using his early microscopes. Plant tissues were studied by others, cork cells by Robert Hooke, and viruses are too small to be seen with his early microscopes.

Answer:

a. Living microorganisms