The most appropriate use for radio telemetry among the options provided is 3. Tracking individual animals.
Radio telemetry is a technique used to monitor the movements and behavior of animals by attaching radio transmitters to them. This technology is particularly useful in studies where the animals may be difficult to observe directly or may roam over large areas, making it challenging to gather data on their activities and habits. The other options do not align as closely with the capabilities of radio telemetry.