In a Study on the Bacteria Found in Human Mouths,from

Multiple Choice

In a study on the bacteria found in human mouths,from the Mesolithic to present day,researchers found that Porphyromonas gingivalis,a bacterium associated with tooth decay,is

A) more common in modern times than in either the medieval times or the bronze age.
B) more common in medieval times than in either the bronze age or modern times.
C) more common in the bronze age than in either medieval or modern times.
D) the same frequency in the bronze age, medieval times, and modern times.
E) absent in modern times, but existed in the bronze age and medieval times.