Consider the following activities: 1) Spraying pesticides on a crop field 2) Inspecting the craters of active volcanoes. 3) Collecting breath samples from spouting whales for DNA analysis At the present level of technology, which of the above activities can be successfully carried out by using drones?

All three activities are already being done with drones, so the answer is D. The question's phrase 'at the present level of technology' is the key: it asks what is feasible today, not what is ideal.

• Statement 1 (spraying pesticides): Agricultural drones fitted with spray tanks and nozzles are used for precision spraying. India's push through the Kisan Drone initiatives and the Namo Drone Didi scheme (approved in 2023) shows this is operational, not theoretical.
• Statement 2 (inspecting volcanic craters): Drones with thermal and gas sensors are used to survey active craters where human access is dangerous. Scientists use them to map gas emissions and heat patterns.
• Statement 3 (whale breath samples): Researchers have used hovering multirotor drones to fly through a whale's exhaled blow and collect samples for DNA and hormone analysis. This avoids disturbing the animal with boats.

The core concept is the use of unmanned aerial vehicles for hazardous or inaccessible sampling and surveillance. For Mains GS-III, this links to precision agriculture, disaster management and the Drone Rules framework.

Trap: Candidates tend to assume that only surveillance is possible with drones and reject the spraying and sampling tasks. Read the question's wording on present technology carefully before ruling out an option.