The answer is d I hope this helps
Pathogens are bacteria, viruses, parasites, and fungi that
cannot be seen by the naked eye, be tasted by our sense of taste, nor be
smelled by our noses. These microorganisms’
causes illnesses, especially to their host, the host serves as their food,
shelter and victim. Pathogens are found in wastes, such as hospital wastes or
in the sewages. Pathogens are mostly parasites, which is why they need a host
to survive.