Chains, Ropes, and Slings Test I Source: Questions and answers from the National Safety Council Progress Indicator: Question 4 of 20 4.  A fire produces pressure like a fan and air always flows _______ the point of high to low pressure so the larger the fire the more _______and products of combustion that can be pushed back against the ventilating air towards you and the other firefighters.  (Donald W. Mitchell, Mine Fires 3rd Edition, p. 3) Choices: moves, smoke to, toxins from, heat