If your heart is not strong enough or efficient enough, it is difficult to
stretch
lift weights
breathe
perspire

If your heart is weak and inefficient it can struggle to pump blood to the muscles being used. Without this blood oxygen cannot be delivered to the muscles hence the exercises become very difficult. This is why it is important to look after your heart, and ensure it is healthy before undertaking strenuous exercise.

Well, l think that some effective communication is, emotional barriers and lack of attention, interest distraction or irrelevance. also some physical disabilities such as hearing problems or speech difficulties.      l hope i am correct  and you good luck.

Ithink the answer is c.  hope this is right and