Which of the following parts of a bus anatomy refers to a structure that supports the vehicle?

The skeletal system of a vehicle, akin to biological skeletal systems, refers to the structure that provides support and stability. In the context of a bus, this implies the framework that maintains the overall integrity and shape of the vehicle. It includes fundamental components that are essential for carrying the load of the bus and its passengers while also ensuring durability and safety during operation.

In contrast, other terms such as "Body on Chassis," "Integral Body," and "Platform Assembly" relate to the configuration and design of vehicles but do not specifically denote the supportive framework. "Body on Chassis" refers to a design where the body is mounted on a separate chassis, and "Integral Body" implies that the body and chassis are unified into a single structure. These concepts are more about the configuration rather than the skeletal structure that offers support. "Platform Assembly" generally denotes the base or layout for mounting various components but does not specifically highlight the overall supportive function as the skeletal system does. Thus, recognizing the skeletal system as the correct answer emphasizes its role in providing the essential support structure for the bus.