Final answer:
A communicable disease is a type of infectious disease that can be transmitted from person to person, either directly or indirectly, and includes both highly contagious diseases like measles and less contagious ones like gonorrhea.
Step-by-step explanation:
A communicable disease is an infectious disease caused by pathogenic microorganisms, such as bacteria, viruses, parasites, or fungi, that can be spread, directly or indirectly, from one person to another. Communicable diseases may also be referred to as contagious diseases, especially when they are easily transmitted. A classic example of a highly contagious disease is measles, which is spread through respiratory droplets when an infected individual coughs or sneezes. On the other hand, diseases such as gonorrhea require close intimate contact for transmission and are therefore considered less contagious. Antibiotics are used to treat bacterial infections and some other types of pathogens but are ineffective against viral infections, such as the common cold or influenza.