What describes unibody construction in automobiles?

• A. A frame and body that are separate components.
• B. The frame and body form one integral unit.
• C. A body-on-frame design where the body is built on a separate frame.
• D. A modular frame with detachable panels.

Answer: (B)

Unibody construction means the vehicle’s frame and body are built as one integrated structure. The body itself carries the primary loads, with floor panels and structural members forming a single rigid shell. This setup distributes crash and operating forces across the entire unit, giving better rigidity, lighter weight, and improved handling and safety—reasons why most modern passenger cars use unibody design. In contrast, a frame-and-body separate design (body-on-frame) uses a distinct chassis that the body sits on, which is heavier and more common in trucks and traditional SUVs. A modular frame with detachable panels describes another concept that isn’t the same as unibody, which is defined by the absence of a separate, load-bearing frame.