Hydrogels have been in the news for their diverse applications. Recently, hydrogels were in the news for their application in developing glucose-measuring technique in smartphones. Hydrogels are cross-linked polymeric networks swollen in biological fluid. They are widely used in the field of medicine. However, their uses are varied. This class of materials is used for local drug delivery because they provide high biocompatibility , drug protection , spatiotemporal control of the drug release , and physicochemical tailorability. Option 1 is correct: Hydrophilic polymeric networks that are capable of imbibing huge volumes of water and undergoing swelling and shrinkage suitably to facilitate controlled drug-release are called hydrogels. Their porosity and compatibility with aqueous environments make them highly attractive bio-compatible drug delivery vehicles. Option 2 is correct: Due to its water-absorbing properties hydrogels may be used to cool down electronic items. Option 3 is correct: Researches show hydrogels can be used as lubricants because of their excellent anti- friction and anti-wear properties.