The spread of pathogens how do we get sick worksheet answers

Pathogens are any microorganisms that cause disease. These include viruses, bacteria, and parasites. They can spread via contaminated food and water; from one sick person to a healthy person; through contact with blood-containing pathogens; endogenous infection during an immunocompromised state.

Water- and food-borne pathogens are spread via uncooked meat, improperly washed fruits and vegetables, and unsanitary practices of food handlers.

Blood-borne pathogens are spread via vectors like mosquitos, and accidental injections of dirty syringes that were used on patients with hepatitis B or HIV.

A person can be immunocompromised when the patient is undergoing chemotherapy, chronic or prolonged use of corticosteroids, or if he or she is simply born with a weak immune system. In this state, the person can easily be infected with normally harmless bacteria that live inside of us. 

Iam not sure but to me it with be a or dsorry if i was late! hope this ! : )if you really want me to find out the answer that is correct tell me and i will do more research but the a or d makes sense to me.