D) increased breathing rate for a shorter period of time
<em>Immunization</em><em> </em><em>records</em><em> </em><em>should</em><em> </em><em>be</em><em> </em><em>kept</em><em> </em><em><u>until</u></em><em><u> </u></em><em><u>the</u></em><em><u> </u></em><em><u>age</u></em><em><u> </u></em><em><u>of</u></em><em><u> </u></em><em><u>maturity</u></em><em><u>.</u></em>
<span>Since I do not know your maximum heartrate ill give you the standard. For vigorous-intensity physical activity, a person's target heart rate should be 70 to 85% of his or her maximum heart rate.</span>