Speculate about some of the possible consequences that a great and prolonged increase in explosive volcanic activity might have on each of Earth's four spheres.

Based on the cause-and-effect relationship in this sentence, what is the meaning of the word illuminate? the colors and patterns on the stained glass windows were illuminated as thousands of candles burned during the special church service. a) to melt or change form b) to grow taller or wider c) to become extremely hot d) to light up or make clear