Q. In which of the following are hydrogels used?
  1. Controlled drug delivery in patients
  2. Mobile air-conditioning systems
  3. Preparation of industrial lubricants
Select the correct answer using the code given below: (UPSC Prelims 2024)

Answer: 1 only
Notes: The correct answer is [A] 1 only. Hydrogels are three-dimensional network polymers capable of absorbing and retaining large amounts of water or biological fluids.Hydrogels are increasingly important in "smart" technologies, specifically in agriculture (soil moisture retention), hygiene products (diapers), and tissue engineering, but their role in heavy industrial cooling or lubrication is not a standard application.