Describe how Leeuwenhoek's discovery of life in a drop of water led to the future scientist to the germ theory of disease?

Answer: germ theory

Explanation: Germ theory of disease is a theory in biology. It says that small organisms (called germs), also known as microbes, cause diseases. Most, but not all diseases are infectious diseases. The germ theory states that small organisms cause a reaction in the body of those who are infected. The body's reaction to infection is called a disease.

Reference: Wikipedia