Concept:Magnets attract ferromagnetic materials such as iron, nickel, and cobalt, while heating or hammering can cause loss of magnetism.
Explanation:Statement A is correct because heating randomizes the aligned magnetic domains, causing the magnet to lose its properties.
Statement B is correct because bar magnets are stored in pairs with unlike poles on the same side to reduce demagnetization and maintain strength.
Statement C is correct because similar poles of magnets always repel each other.
Statement D is incorrect because nickel and cobalt are ferromagnetic metals and are strongly attracted by magnets.
Answer:The incorrect statement is: D. Nickel and Cobalt do not get attracted by magnet.