Rae is training for cheerleading, so she starts rollerblading for 45 minutes each day. her heart rate reaches 128 beats per minute, but her target heart rate zone is 140—178 beats per minute. which of the following could she do to get a greater benefit during her 45-minute activity?

answer; i believe the correct answer is (secondary prevention);

well when looking at this if you think about it   negativley and positivley   react with each other and when the first layer gets full they add layers it starts with 2 on the first layer and it constantly goes on until the official number is there