Which type of lever has the fulcrum located between the effort and resistance forces?

The type of lever that has the fulcrum located between the effort and resistance forces is indeed the first-class lever. In this configuration, the load and effort are on opposite sides of the fulcrum. This arrangement allows for a mechanical advantage, depending on the distances from the fulcrum to the points where the effort and resistance are applied.

Common examples of first-class levers include seesaws and scissors, where the fulcrum is centrally positioned between the two forces. The design of a first-class lever enables balance and movement by allowing a smaller effort force to move a larger load force when applied at an appropriate distance from the fulcrum.

Second-class levers have the load located between the fulcrum and the effort, which provides different mechanical advantages. Third-class levers, conversely, have the effort applied between the fulcrum and the load, making them less efficient in terms of mechanical advantage but beneficial for increased range of motion or speed in the output. A compound lever consists of two or more simple levers working together, but it does not fit the specific description given in the question.