Never mind I figured it out. A supply of copper pipes is stored outdoors. Over the course of many years, the copper reacts with oxygen and turns green. What clue indicates a chemical reaction took place? copper reacts with oxygen

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange

What type of context clue you understand the meaning of  quandary?

Which statement would indicate the presence of an acid