Substances that are readily combustible or may cause fire through friction

Answer :

Flammable substances

Explanation :

Flammable substances will catch fire and continue to burn when they contact an ignition source like a spark or a flame.

For example, methanol is a flammable liquid.

A flammable solid may also catch fire through friction. Matches are flammable solids.

the transfer of heat by electromagnetic radiation is called thermal radiation . it is usually carried out by electromagnetic waves in an energy range just below the visible spectrum, which is the infrared range.

so the answer would be radiation.

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