A)are infections transmitted by insects.
B)are infections acquired from animals.
C)can be spread by aerosols.
D)may be caused by a toxin.
E)all of the above.

A)Pathogens that cause disease in humans cannot survive outside the human body.
B)Communicable diseases are only caused by pathogens which are able to survive outside the human body.
C)To cause disease pathogenic microorganisms must be transmitted directly from person to person.
D)Opportunistic pathogens always cause disease.
E)None of the above.

A)Smallpox.
B)Chickenpox.
C)German measles.
D)Typhoid.
E)Meningitis.