Which type of ladder can be extended to reach a desired height and consists of two or more sections?

An extension ladder is specifically designed to reach greater heights by allowing the user to extend and lock multiple sections of the ladder into position. This feature makes it ideal for reaching elevated areas, such as rooftops of buildings or high windows. The ability to adjust the length provides versatility, enabling firefighting personnel to adapt to various situations and increased reach without requiring multiple fixed-length ladders.

In contrast, other types of ladders listed serve different purposes. A combination ladder can function as both an extension and a step ladder but does not specifically highlight the extension mechanism. A roof ladder is specialized for use on sloped roofs and has hooks to secure it, while a folding ladder is designed for compact storage and transport, lacking the multiple extended sections of the extension ladder. Thus, the extension ladder is uniquely suited for applications where height adjustment is crucial.