Answer the following question given this paragraph: 

Worldwide, the most common disease caused by bacteria is tuberculosis (TB). TB is a serious disease of the lungs. Another common disease caused by bacteria is strep throat. You may have had strep throat yourself. Bacteria that cause strep throat are shown below ( Figure below ). Some types of pneumonia and many cases of illnesses from food are also caused by bacteria.


Q: What type of organism causes many common diseases such as strep throat and food-borne illnesses?


A:
bacteria