A lightweight material is being tested for effectiveness in blocking utraviolet (UV)rays from the Sun that cause skin to burn and possibly develop skin cancer. Which method would be most helpful for lesting this material? Use specialized equipment to measure how much UV light passes through stacks of one, five, or 20 layers of the material. Test the materialin controlled natural settings by using natural UV light, and measure the UV light that passes through. Write a survey that asks people on beaches about their preferences for sunscreen and protective materials. 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 best method for testing the material's effectiveness in blocking UV rays is **A. Use specialized equipment to measure how much UV light passes through stacks of one, five, or 20 layers of the material.**<br /><br />Here's why:<br /><br />* **Controlled Environment:** A lab setting allows for precise control of the UV light source, ensuring consistent and repeatable results. Using specialized equipment provides accurate measurements of the UV light that penetrates the material. Testing different numbers of layers helps determine the material's effectiveness at different thicknesses.<br />* **Objective Measurement:** Measuring UV light penetration directly provides objective data, eliminating subjective biases that could arise from human perception of skin damage or sunscreen preferences.<br />* **Safety and Ethics:** Options C and D involve human subjects, which introduces ethical considerations and potential health risks. Directly measuring UV light penetration avoids these concerns.<br />* **Efficiency:** Option B, while using a natural UV source, lacks the control of a lab setting. Weather conditions, time of day, and other environmental factors can influence UV intensity, making results less reliable. Option C (the survey) is irrelevant to the material's effectiveness in blocking UV rays.<br />