Because both of them want to be controlling all the time
because both want to always be right most of the time
Here you go
............................
<span>A players batting average will be positively correlated with the time spent on batting practice.</span>
Cardiovascular system has to do with the heart, so anything to reduce the risk of that system (including the heart, bloodstream etc.) would be the answer for you. So just using Process of elimination:
A) Has to do with external exposure. <em>No</em><em />
B) Keeping hands clean <em>No</em><em />
C) Avoiding cigarette smoke <em>Yes</em>
D) Keeping your vaccinations up to date <em>No</em><em />
So your answer is C.
