Abney level is used for the measurement of: (CG RHEO 2017)

✅Explanation: The Abney level is a clinometer, primarily designed to measure slopes and vertical angles. It achieves this through a combination of:
-Sighting tube: Allows the user to align their vision with a target point.
-Movable level: Indicates when the instrument is level.
-Graduated scale: Reads the angle of the sighting tube relative to the level, providing the slope measurement.