Some of the new cars being made can run on a renewable fuel that is made mostly from corn. Scientists are developing even more renewable fuels to replace gasoline. Why are renewable fuels most likely becoming more important?
A: Nonrenewable fuel supplies are limited.

Examine each of these chemical equations to determine which equation is correctly balanced.
A: Mg(NO_{3})_{2} + K_{2}CO_{3} -> MgCO_{3} + 2KNO_{3}

During which phase change is heat energy absorbed by a substance?
A: liquid to gas

Which of these indicates a physical change that occurs during the process of digestion?
A:
the squeezing of food through the intestines