Ellie is visiting the Grand Canyon on her summer vacation. Everyone in her tour group marvels at the different rock layers and colors within the canyon. A lot of them are wondering, "Why do the layers vary in color?” How could Ellie use the scientific inquiry process to find out? Check all that apply. She could research what geologists have already discovered about the canyon. She could match the colors with those of other objects at home. She could hike into the canyon and make observations of the rocks in each layer. She could ask other visitors what they think about why the colors vary. She could compare her observations of the rock layers to other rock layers in the area.