Which term best characterize a microorganism that causes disease primarily when a host's immune defenses are weakened or when it reaches an unusual body site?

Which of the vaccines listed below is generally recommended as a priority for college students?

When microorganisms are present on a host but do not trigger an immune response or illness, this is referred to as:

When animals raised for food carry bacteria that are resistant to antibiotics, these organisms are MOST likely to be transmitted to people:

True or False: Pneumonia may result from viruses, bacteria, fungi, or inhaling chemical substances.

Which statement about viruses is TRUE? 

Identify the statement below about the common cold that is incorrect.

Select the best pair of reasons that support public vaccination programs against lethal infectious diseases.