You are investigating the role of physical activity in heart disease and suggest that physical activity protects against having a heart attack. while presenting these data to your colleagues, someone asks if you have thought about confounders such as factor x. this factor x could have confounded your interpretation of the data if it:

True it's the strategy

The answer would be c (set)hope this ! (:

I’m going to guess these are the choices: a) recreational skiing developed in the mid-19th century b) it was originally invented as a way of getting from place to place in snowy regions c) downhill skiing is currently the only common form of the sport d) it mostly evolved from snowshoeing- if that’s the cases then the answer would be c) downhill skiing is currently the only common form of the sport