When you breathe in and out you're using your lungs

i would say b

explanation:

but i think i would need more information than that

he would use the colour black

because natural gas is colorless, odorless, and tasteless, distributors add mercaptan (a chemical that smells like sulfur) to give natural gas a distinct unpleasant odor (it smells like rotten eggs). they locate the types of rock that are likely to contain natural gas deposits.