Nate Core Practice Test 2025 - Free Practice Questions and Study Guide

In construction, a horizontal structural member primarily serves the purpose of supporting loads and transferring them to vertical elements such as columns or walls. The correct choice, which is the joist, is specifically designed to span open spaces and support floor or ceiling structures. Joists are crucial in the framing of buildings as they provide stability and support for surfaces above them, commonly seen in floors and roofs.

While beams also act as horizontal members, they are typically larger and might be used for different purposes, such as carrying heavier loads over greater spans. A column, on the other hand, is a vertical component designed to support overhead structures directly and does not fit the description of a horizontal member. Trusses, while they can have horizontal components, are primarily a framework of interconnected vertical and diagonal elements which distribute loads efficiently, often used in roof designs.

Thus, the key characteristic of a joist being specifically a horizontal structural member that directly supports flooring or ceiling loads clarifies its importance and function in construction.