Answer: 3. researching the relationship between exposure to UV rays and skin cancer.
Explanation:
Applied research is an application based research as it utilizes the knowledge of scientific literature to solve the problems related to science. It is based upon the experimental procedure to find the cause of a natural phenomena.
Researching the ralationship between exposure to UV rays and skin rays. is the correct answer because it can be observed on the basis of experimental procedures the impact of UV under control conditions over the skin.