Lyme disease is caused by bacteria that enter the body of a human host while a tick is attached and feeding. The bacteria move into the host's bloodstream and are carried to many different parts of the body. There, they cause varying symptoms. Lyme disease infects animals such as mice, deer, squirrels, and opossums.
<span>Which
of the following is not a reason why communicable diseases, such as
pneumonia, killer fewer people today than they did in the past?
B </span>
