Detailed Explanation:

Answer: Option 4 — 1,2 and 3

All three activities mentioned can be successfully carried out using drones at the current level of technology. Drones have revolutionized various fields by enabling safe, efficient, and cost-effective operations in environments that are hazardous, remote, or difficult to access for humans.

✅ Statement 1 – Correct: Agricultural drones are extensively used for precision spraying of pesticides and fertilizers on crop fields, reducing chemical waste and human exposure to toxins.
✅ Statement 2 – Correct: Drones equipped with thermal cameras and gas sensors are deployed to inspect active volcano craters, allowing scientists to collect critical data from dangerous environments without risking human lives.
✅ Statement 3 – Correct: Specialized drones like 'SnotBot' are used to fly through whale blows (spouting breath) to collect biological samples including DNA, hormones, and microbiomes for non-invasive health monitoring and research.

📝 Short Notes: Applications of Drones (UAVs)

• Agriculture: Precision spraying of pesticides/fertilizers, crop monitoring, soil analysis, and irrigation management
• Environmental Research: Volcano monitoring, wildlife tracking, forest fire detection, and air quality assessment
• Marine Biology: Whale health monitoring through breath sample collection, marine mammal surveys, and coral reef mapping
• Disaster Management: Search and rescue operations, damage assessment, and delivery of emergency supplies
• Infrastructure: Inspection of bridges, power lines, pipelines, and tall structures
• Delivery Services: Medical supplies, e-commerce parcels, and food delivery in remote areas
• Defense & Security: Surveillance, reconnaissance, border patrolling, and tactical operations