Which of the following describes thermoplastics?

Thermoplastics are characterized by their ability to be remoulded and reshaped when heated, which makes option A the correct description. This property stems from the molecular structure of thermoplastics, where the polymer chains are not tightly bonded, allowing them to move and flow when subjected to heat. This capability enables processes like injection molding and extrusion, which are commonly used in manufacturing various plastic products.

In contrast, thermoplastics do not have a fixed melting point; instead, they soften over a temperature range. This distinguishes them from thermosetting plastics, which cannot be remoulded once set. Additionally, thermoplastics can be recycled, as they may be reheated and formed into new products, contradicting the idea presented in option C. Lastly, while some thermoplastics exhibit chemical resistance, they are not universally inert at all temperatures; certain types can degrade or react under extreme conditions, making option B inaccurate.