POLIO BEFORE AND AFTER THE VACCINE
3. What trend does the graph show? What explains the trend?
between the year 1950 to 1963
Reported Number of Cases
Per 100,000 People
is from 0 to
3. What trend does the graph show? What explains the trend?
between the year 1950 to 1963
Reported Number of Cases
Per 100,000 People
is from 0 to