Iron. Iron is not a cancer causing substance while arsenic, nickel and polonium are.
Well because this is health I am assuming they are referring to the health side of the sport. The concussion rate in the sport is super high, higher than most sports even with the padding and helmet protection. It is also a high contact sport so injuries are bound to happen.
Answer:
Why is it important to get a resting respiratory rate as a vital sign rather than a rate while a person is active?
Well, because it shows your heart is actually resting.
