What makes the yardstick test a direct measurement of reaction time?
a.
the further the yardstick falls, the slower the reaction time.
b.
yardsticks have numerical markings for length.
c.
yardsticks are designed to measure reaction time.
d.
all of the above

The answer is A. The further the yardstick falls, the slower the reaction time.

when in a crucial situation, after calling 911, the correct posture for delivering effective compression is the proper hand placement.

first, place two fingers at the sternum, then put the heel of your other hand next to the fingers and place hand on top of the other. lock your elbows by using your body’s weight and compress the victim’s chest with a depth of 2 inches.

moreover, do 15 compression and 2 breaths, this process must be done four times until there is a pulse or a arrive.