The gradient of land can be measured with an instrument called a/an

Step 1: Analyze the question The question asks for the instrument used to measure the gradient (slope or steepness) of land. This is an ecology topic, where abiotic (physical) factors of a habitat are measured.

Step 2: Review each instrument

• A. Aneroid barometer: measures atmospheric pressure, and can estimate altitude. It does not measure slope.
• B. Hygrometer: measures humidity (moisture in the air).
• C. Metre rule: measures length or distance, not angle or steepness.
• D. Secchi disc: measures water turbidity (clarity) in lakes and ponds.
• E. Slope gauge: measures the angle of inclination of the ground, which is its gradient.

Step 3: Identify the answer Gradient means the angle or steepness of the land surface. Only a slope gauge (a clinometer-type device) measures this directly.

Answer: E. Slope gauge

Exam tip: Match each instrument to what it measures:

• Barometer → air pressure
• Hygrometer → humidity
• Secchi disc → water clarity
• Anemometer → wind speed
• Thermometer → temperature
• Slope gauge/clinometer → slope or gradient

Questions like this are easy marks if you learn this list.