Over the past century,a marked decline in the mortality rates of many infectious diseases has been observed.Which of the following is the most likely reason for the observed decline in mortality rates from common infectious diseases?
A) Development of penicillin
B) Development of insulin
C) Development of vaccines
D) Improvement in social conditions
E) Worse sanitation and unsafe water

Question

Quizplus · Accepted Answer

The Answer is D

Over the Past Century,a Marked Decline in the Mortality Rates