What component turns rotary motion of the crankshaft into up and down motion?

The correct answer is the piston. The piston is a critical component within an engine that converts the rotary motion generated by the crankshaft into the up-and-down motion needed for the engine's power cycle. When the crankshaft rotates, it drives the connecting rods, which are attached to the pistons. As the crankshaft turns, it pushes the piston up and down within the cylinder, facilitating the intake and exhaust processes necessary for combustion and engine operation.

While the camshaft, cylinder, and engine block are essential parts of the engine, they do not perform this specific function. The camshaft primarily controls the timing of the opening and closing of the engine's valves based on its rotation. The cylinder houses the piston and provides the space for combustion but does not convert motion on its own. The engine block serves as the main structure that contains the cylinders and supports various engine components but is not involved in the conversion of motion. Thus, the piston is the correct answer because it directly fulfills the role of translating rotary motion into linear motion essential for the engine's function.