C and D
surface water is evaporated by the sun and concentrated the ocean salt and oceans are diluted when rivers flow into them
Microgravity is your answer
Your answer is the last option, the explosion of fireworks. This is because all of the other options are physical changes because they don't change the substance, they only affect it in some way. However the explosion of a firework clearly changes a substance inside the initial 'rocket' into fireworks.
I hope this helps!
A layer above the earth that protects the planet from dangerous UV that are sent from the sun
