Question

how fire is not useful to us
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Answer 1

Fires require oxygen and fuel to be ignited. With oxygen present in the air, faulty electrical wiring, cigarette butts, static electricity, and even concentrated sunlight can act as fuel and a destructive fire can start. Fires are made more deadly by smoke and toxic gases emitted from consumed materials. According to the U.S. Fire Administration (part of FEMA), there were 1.3 million fires in 2015 that led to 3,280 deaths, 15,700 injuries and more than $14 billion in damages.

Answer 2

you question has no answer because there is a very useful but dangerous dangerous substance because of the reaction between some chemicals such as petrol and fire reacts very easily so that it catches fire very easily so fire with petrol it has ignition temperature