What is the term for previously established elevation points in surveying?

Answer: A — Bench Marks

The term for previously established elevation points in surveying is "bench marks." Bench marks are specific locations where the elevation has been accurately measured and recorded, serving as a point of reference for future surveying activities. These points are crucial in establishing control for leveling work, providing a means to ensure consistency and accuracy in elevation measurements across different surveying tasks. Bench marks are typically marked on a durable material, such as concrete or metal, and they are distributed across the landscape to create a reliable framework for various project needs, including construction, engineering, and geographic mapping. Their use allows surveyors and engineers to relate other measurements back to a known, fixed elevation, which is essential for the design and construction of infrastructure like roads, bridges, and buildings.