Answer:
Research the cause of cancer
Explanation:
The definition of epidemiologist is "scientists who study diseases within populations of people."
AED is the correct answer
Target weight loss is one method.
I believe it would be C. Cracking a rib.
Because
- CPR doesn't involve the arms
- Headaches can happen at any age
- Not finding a pulse can happen with any person
- Cracking a rib would make the most sense to me due to that bone mass or density decreases as a person ages, the bones lose calcium and minerals causing them to deteriorate and become more brittle, which may result in them becoming easily breakable.
This is only my guess though, so don't take my word for it.
Hope it helps at least a little. (: