Respuesta :

Flammable solids, substances that are dangerous when wet, and spontaneously combustible materials are Class 4 materials.

Class 4 materials burn without external changes in density or pressure. They are also prone to incineration without the aid of chemical accelerators.

Class 4 materials burn without external changes in density or pressure. They are also susceptible to incineration without the aid of chemical accelerators.

Learn more about combustible materials here: https://brainly.com/question/10503642

#SPJ4