Question

you are doing a lab with a bunsen burner and something catches fire. what should you do first?

Explanation:

In a lab fire situation with a Bunsen burner, cutting off the fuel source is crucial to prevent the fire from getting worse. Turning off the gas supply to the Bunsen burner is the first - step as it removes the fuel that is feeding the fire.

Answer:

Turn off the gas supply to the Bunsen burner.