Doctors once believed that illness was caused by foul air and could not be transmitted from one person to another. Now, doctors know that single-celled bacteria and even smaller viruses cause illnesses and can be transmitted from one person to another.How did the advent of the microscope most likely affect the foul-air theory?
Answer
A
It supported the theory of foul air causing illness and helped the theory become a law.
B
It provided evidence for other causes of illness, but scientists did not change the theory.
C
It allowed scientists to change the theory before any new information was collected.
D
It allowed scientists to see small organisms in sick individuals and change the theory.