Answer the following question given this paragraph: 

Infectious diseases are diseases that are caused by pathogens. Human pathogens include bacteria, viruses, fungi, and protozoa. Different pathogens spread in different ways. Pathogens may spread through contaminated food or water, sexual contact, droplets in the air from coughs or sneezes, contaminated objects or surfaces, or vectors.


Q: What type of disease is caused by pathogens?

 Choices:

- viral diseases

- nervous diseases

- autoimmune diseases

- infectious diseases

A:
infectious diseases
