Within an internal combustion engine, the can-shaped component that moves up and down the cylinder and is the main moving part in the engine is the
a. connecting rod.
b. piston.
c. spark plug.
d. crankshaft.

Piston is the part in the combustion engine which moves up and down. Piston is connected in connecting rod which helps to move it.
Spark plugs are used to produce spark.

So the answer is B. Piston

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