Explanation -Recycling: The process of transforming waste resources into new materials and things is known as recycling.The ability of a substance to reclaim the qualities it had in its original form determines its recyclability.It's a greener alternative to "traditional" garbage disposal that saves resources and reduces greenhouse gas emissions.Recycling reduces energy consumption, air pollution (from incineration), and water pollution by preventing the waste of potentially valuable materials and minimising the use of fresh raw resources (from landfilling)Recycling is the third component of the "Reduce, Reuse, and Recycle" waste hierarchy and is an important part of modern waste reduction.By substituting raw material inputs and moving waste outputs out of the economic system, recycling tries to achieve environmental sustainability.A recyclable resource is thus a material that can be used repeatedly after going through a process to make it ready for reuse.The process can be induced by humans or occur naturally or spontaneously.Examples of recyclable materials: Iron scraps like keys, sheets, kitchen pans or pots or tins etc; aluminium; certain plastics; old newspapers etc. As Iron is a recyclable material, the correct answer to this question is - iron.