A single ladder is essentially the same as which part of an extension ladder?

A single ladder is essentially the same as the base section of an extension ladder because both serve as the foundational component that provides stability and support while in use. The base section is designed to rest on the ground, and it is crucial for maintaining balance and preventing accidents when the ladder is in use.

In contrast, the fly section of an extension ladder is the part that extends outwards to reach higher areas, making it different in function as it is not designed to rest on the ground like a single ladder. The middle section can vary in length and does not provide the same stable support as the base section. The upper section, typically a part of a larger ladder system, serves to reach heights but similarly does not match the function of a standalone single ladder. Understanding the distinction between these sections is important for safe ladder usage.