Question

what weather instrument is used to determine how much rain has fallen over a period of time?
○ rain gauge
○ weather balloon
○ radar
○ thermometer

Explanation:

A rain gauge is specifically designed to measure the amount of rainfall over a period. A weather balloon is used to collect data about the atmosphere aloft, radar is used for detecting precipitation, clouds, etc., and a thermometer measures temperature. So the correct instrument for measuring rainfall is a rain gauge.

Answer:

A. Rain Gauge