Problem: -  The boiler produces steam under high pressure - The steam generated in the boiler flows down into a cylinder - Just ahead of the wheels, pushing a tight-fitting plunger, the piston - The piston is connected to one or more of the locomotive&#x27;s wheels through a kind of arm-elbow-shoulder joint called a crank and connecting rod - As the piston pushes, the crank and connecting rod turn the locomotive&#x27;s wheels and power the train along - An outlet valve opens and the piston pushes the steam back through the cylinder and out up the locomotive&#x27;s chimney -   What might be the first step of the process?

A: Coal is loaded into the firebox


Problem: -  The plants and floor absorb the the sunlight - The absorbed sunlight is converted to heat - The heat cannot escape the glass - The heat is trapped in the greenhouse - The hot air rises - The colder air at the top is pushed to the bottom - The colder air is then warmed by the floor and the plants.  What might be the first step of the process?

A: Sunlight passes through the glass into the greenhouse


Problem: -  The water is boiled to a very high tempature - The salt becomes seperated from the water - The salt is removed - The water is able to be drank at this point.  What might be the first step of the process?

A: Salt water is contained in a factory or plant


Problem: -  The sediment rolls down hill towards a river - The heavy items sink to the bottom - The lighter items float on the top and in convection cycles - As the river flows the sediment is moved - The sediment gets dumped through tributaries into lakes and the ocean - The sediment keeps moving around the world in convection currents.  What might be the first step of the process?

A:
Sediment becomes loose from the rest of the soil