Alightweight material is being tested for effectiveness in blocking ultraviolet (uv) rays from the sun that cause skin to burn and possibly develop skin cancer. which method would be most for testing this material?

a) use specialized equipment to measure how much uv light passes through stacks of one, five, or 20 layers of the material.
b) test the material in controlled natural settings by using natural uv light, and measure the uv light that passes through.
c) write a survey that asks people on beaches about their preferences for sunscreen and protective materials.
d) test the material in a lab setting by using humans and a variety of uv light sources, and develop a scale to measure the damage that is caused to human skin.

B) Test the material in controlled natural settings by using natural UV light, and measure the UV light that passes through.  

Ultraviolet rays are radiations from sun that the earth receives. These radiations have a direct impact on human skin, these are able to cause mutations in human genome and are carcinogenic in nature. A lightweight material can be tested in controlled natural settings by using natural UV light like skin cells can be observed under two conditions. In controlled condition a skin cell which is not coated with light weight material and in experimental skin cell which is coated with lightweight material.  If these cells are exposed to different ranges of UV radiations will help in deducing important conclusion regarding the usefulness of light weight material in blocking sunlight. The controlled cell will die because it is not tolerant to UV rays. The experimental skin cell will either survive or die. If it survives then, it can be concluded that the light weight material is effective in blocking UV rays and if it dies then, a light weight material is not effective in blocking UV rays.

Therefore, testing the material in controlled natural setting by using natural UV light, and measures the UV light passes through would be the most helpful method for testing the material.

answerlength of time the medication is in contact with the skin(moistur level of the skin) depth of respirations blood supply to the area; all of the above; ///