Consider the following activities: 1. Identification of narcotics on passengers at airports or in aircraft 2. Monitoring of precipitation 3. Tracking the migration of animals. In how many of the above activities can the radars be used?

Radars can be used in all three activities. Specialized radars and millimeter-wave scanners at airports can detect concealed substances including narcotics on passengers. Weather radars (such as Doppler radars) extensively monitor precipitation, storms, and rainfall patterns. Tracking animal migration is also done using radar — biologists use radar ornithology to track bird and insect migrations, and tagged animals can be tracked using radar systems. Hence all three applications are valid uses of radar technology.