Question

what causes infectious disease?
cells
invaders
nonpathogens
pathogens

Explanation:

Infectious diseases are caused by pathogens, which are organisms like bacteria, viruses, fungi, or parasites that can invade the body and cause illness. Cells are normal components of the body, non - pathogens do not cause disease, and "invaders" is a very general term. Pathogens are the specific cause of infectious diseases.

Answer:

D. Pathogens