The correct answer is A. thermoplastic.
Thermoplastics are a type of plastic that can be melted and reshaped multiple times. They are made from long chains of molecules that are held together by weak bonds. When heat is applied, these bonds break and the plastic can be melted and molded into a new shape. Once the plastic cools, the bonds reform and the plastic retains its new shape.
Thermosets, on the other hand, are a type of plastic that cannot be melted and reshaped once they have been formed. They are made from long chains of molecules that are held together by strong bonds. When heat is applied, these bonds do not break and the plastic cannot be melted. Thermosets are typically used for applications where a strong, durable material is needed, such as in car parts and appliances.
Chemical compounds are substances that are made up of two or more elements. They can be either organic or inorganic. Organic compounds contain carbon, while inorganic compounds do not. Polymers are a type of chemical compound that is made up of long chains of molecules. They can be either natural or synthetic. Natural polymers include cellulose, which is found in plants, and proteins, which are found in animals. Synthetic polymers include plastics, such as polyethylene and polypropylene.
In conclusion, the material which can be deformed permanently by heat and pressure is called a thermoplastic.