Which step of the scientific method involves identifying variables

Difference between series and parallel circuits

The three classes of rocks are sedimentary, metamorphic, and igneous. how are rocks classified into one of these three groups?

Listed following are various physical situations that describe how light interacts with matter. match these to the appropriate category. 1) transmission? -visible light meets clear glass -visible light does not pass through a black wall -red light hits a red sweatshirt -light comes from your computer screen -cell phone signals pass through walls -blue light hits a red sweatshirt -white light hits a white piece of paper -light comes from a light bulb