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?

Answer: D. All three activities can be carried out by drones at the current state of technology. DRONES (Unmanned Aerial Vehicles) have rapidly become a versatile platform for a wide range of civilian and scientific applications. (1) SPRAYING PESTICIDES ON A CROP FIELD: CORRECT. AGRICULTURAL DRONES (such as DJI Agras, Yamaha RMAX) are widely used to spray pesticides, fertilisers and seeds over crops. Drones can apply pesticides more uniformly than ground sprayers, reach areas (paddy, tea, hilly terrain) where tractors cannot, reduce human exposure to chemicals, and use precision targeting to minimise total volume sprayed. India's Ministry of Agriculture has issued SOP for drone use in pesticide spraying, and the 'Kisan Drone' programme promotes adoption. ICAR, IIT-Madras and others have demonstrated effective drone spraying. (2) INSPECTING THE CRATERS OF ACTIVE VOLCANOES: CORRECT. Drones are routinely deployed to monitor volcanoes whose crater interiors are too dangerous for humans. Drones equipped with thermal cameras, gas sensors (SO2, CO2, H2S), LIDAR, and high-resolution imagery have flown into active craters at Mount Etna, Stromboli, Sakurajima, Anak Krakatau and Kilauea. They map crater morphology, sample volcanic gases, detect early signs of eruption, and provide imagery for hazard assessment. (3) COLLECTING BREATH SAMPLES FROM SPOUTING WHALES FOR DNA ANALYSIS: CORRECT. The 'SNOTBOT' developed by Ocean Alliance (Iain Kerr) is a specialised drone equipped with petri dishes to collect 'BLOW' (the spray from whale spouts), which contains exhaled mucus rich in DNA, hormones, microbes, and viruses. This non-invasive sampling allows scientists to study whale genetics, stress hormones (cortisol), pregnancy, and microbiome without darting or boat-pursuit. The technique has been applied to humpback, sperm, and blue whales globally. So all three are demonstrated drone applications at current technology levels. Source: Ministry of Civil Aviation Drone Rules 2021; Ministry of Agriculture and Farmers Welfare drone advisories; Ocean Alliance SnotBot programme; Smithsonian and Nature publications on drone-assisted research.