A pH scale goes from 0 - 14.
7 is in the middle so it is neutral
Coals energy is affordable and it is easy to burn.
1. D - sound travels the fastest through solids
2. 50 mm/s - v=fa
3. B - only process that involves changing waves
On a worldwide scale, the most common fuels are wood, grass, peat, coal, and animal fats and oils.