Cooking gas
pure substances or mixtures​

Cooking gas is a Mixture

Explanation:

A pure substance is a substance which contains definite composition of only one type of component. Hence, it cannot be separated by physical means.

On the other hand, a mixture is a substance which contains two or more than two types of components and they can be separated by physical means as well.

Cooking gas is a made up of a combination of different hydrocarbons (methane, ethane , butane etc)  and thus is a mixture.

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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