Problem: - Particles in the environment interact with rocks - The particles remove small pieces of the rock each time they touch the rocks - The particles continue to hit, brush against, or grow against the rocks - The rock eventually is broken apart by this contact - The pieces of the rock are now small rocks What might be the last step of the process?

A: The rock pieces are worn away into smaller and smaller pieces by the same forces

Problem: - A mine is excavated in the side of a mountain - Miners enter the mine - Miners remove the coal from the mine - The coal is placed into carts or on a conveyor belt - The coal is moved up to the surface - The coal is loaded onto a truck What might be the last step of the process?

A: The truck takes the coal to a power station.

Problem: - The bat sends out sound waves from their mouth or nose - The sound waves hit an object - Echoes are produced - The echo returns to the bat's ears - The bat hears the echo What might be the last step of the process?

A: The bat can figure out where the object is located.

Problem: - Waste products are deposited in the blood - Blood is carried to the kidneys through the renal arteries - The kidneys contain filters inside - The filters capture the waste products - The waste is combined with water to make urine - The urine leaves the kidney and is collected in the bladder What might be the last step of the process?

A:
The cleaned blood is returned to the body.