Final answer:
A low-slung unit refers to a trailer with a low center of gravity, while a single-axle tractor has only one rear axle. A tandem-axle trailer has two axles for added support.
Step-by-step explanation:
In this question, we are discussing the concept of a low-slung unit and a single-axle tractor pulling a long trailer with its landing gear set to accommodate a tandem-axle trailer.
These terms are commonly used in the transportation industry, specifically in the field of trucking and logistics.
A low-slung unit refers to a type of trailer that is designed to have a low center of gravity, which improves stability and reduces the risk of tipping over.
A single-axle tractor refers to a truck with only one axle on the rear, while a tandem-axle trailer refers to a trailer with two axles for added support.