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?

choices:
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.

The correct answer is statement B.

Explanation:

The UV rays refer to the radiation emitted from the Sun, which the Earth receives. These radiations exhibit a direct influence on human skin, these possess the tendency to produce mutations in human genome and are carcinogenic in characteristic.  

A lightweight substance can be examined in controlled natural environments with the application of natural UV light, like the skin cells that can be observed under two conditions, that is, in controlled condition, in which a skin cell is coated with lightweight material, and in experimental condition, in which skin cell is coated with lightweight substance.  

After exposing these cells to distinct ranges of UV rays, it will assist in finding an important conclusion considering the benefit of the lightweight substance in obstructing sunlight. The controlled cell will die as it is not able to withstand UV rays, while the experimental skin cell will either die or survive.  

In case, if it thrives then it can be deduced that the lightweight substance is efficient in preventing ultraviolet rays, and if it dies, then a lightweight substance is not efficient in preventing UV rays.  

Thus, testing the substance in a controlled natural setting by utilizing UV light, and measuring the UV light passing through would be the most appropriate approach for examining the substance.  

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.