Problem: What is the missing first step of the following process:  -  Coal is pulverized into fine powder - The coal is mixed with hot air - The coal and hot air are blown into a boiler - The coal and hot air burn over a fire - Highly purified water is pumped through pipes in the boiler - The water turns into steam - The steam presses against turbines - The turbines spin - Electricity is produced.

A: Coal is mined out of the ground


Problem: What is the missing first step of the following process:  -  As the plates move, they exert a great force - When the force is large enough, the crust breaks - The stress is released as energy - The energy moves through the Earth in the form of waves - We feel the earthquake -

A: Plates on the Earth&#x27;s crust move slowly past each other


Problem: What is the missing first step of the following process:  -  Magma crystalizes - Lava cools on the surface - Lava crystalizes - Minerals dissolved in water crystlize.

A: Magma cools inside the crust


Problem: What is the missing first step of the following process:  -  Two types of proteins exist in filaments in the muscles - The filaments move when the brain instructs them to - The motion of the filaments cause the muscle to shorten and contract - Opposing pairs of muscles exist in order to provide the necessary range of motion.

A: