Which components make up the power transmission system in a machine?

The power transmission system in a machine consists of all mechanical parts that convey energy and motion. This encompasses various components such as gears, pulleys, belts, chains, and shafts, which work together to transfer energy from one part of the machine to another, ultimately allowing the machine to perform its intended functions.

By focusing on mechanical elements, this answer highlights how these components interact to translate energy into motion. The contribution of these parts is essential because they directly affect the efficiency and effectiveness of the machine's operation.

In contrast, the other choices focus on isolated elements that do not represent the entire system. Electrical parts, while crucial for the functionality of some machines, do not encompass all the necessary components for power transmission, thus they are not sufficient to characterize the entire system. Hydraulic components, like electrical parts, serve a specific function and are not comprehensive of all mechanical parts. Temperature regulation parts, although important for the overall function of a machine, are not involved in the transmission of power.

Thus, understanding the role of all mechanical parts in energy and motion transfer clarifies why this answer is the most complete and accurate representation of the power transmission system in machinery.