Which statement best describes common communicable diseases?
a.
most communicable diseases are either bacterial or viral and infect the respiratory tract.
b.
all communicable diseases are viruses that cause pneumonia.
c.
most communicable disease are bacteria and viruses that infect the intestinal tract.
d.
all communicable diseases are bacteria that grow in the respiratory tract.

The correct answer is A.

Most (but not all) communicable diseases are either bacterial or viral and infect the respiratory tract. Communicable diseases are caused by bacteria, viruses, parasites and fungi that can be spread, directly (sexual intercourse - HIV) or indirectly (from a cough or sneeze - Pneumoina), from one person to another. Some are transmitted through bites from insects (for example Malaria from mosquitoes) while others are caused by ingesting contaminated food or water (salmonella).

that is correct.

answer; (c) all the above