Both Kyla and Tia will be in their zone. Even if they dicrease their heart rates by 20 beats per minute from 175 beats per minute. 155 beats per minute still falls under kyla's target heart rate zone and Tia's target heart rate zone.
I believe the correct answer would be actin filaments. These are polmers that are linear with G-actin as subunits that attaches ith myosin heads during the skeletal muscle contraction. They are necessary for cell shape, adhesion and contraction.
Because it can cause disabilities <span />