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 radars be used?

All three

Radar and related electromagnetic sensing technologies have applications across all three activities. Advanced radar-based or millimetre-wave screening systems can assist in security screening, including the detection of concealed materials. Weather radars monitor precipitation and its movement. Radar systems are also used to study the movement and migration of birds and other animals. Therefore, all three activities can involve radar-based technologies. Options A and B are incorrect because they exclude valid applications. Option D is incorrect because radar is widely used in meteorology and wildlife monitoring.