Approximately how old is the sun?
a. 1.4 billion years
b. 2.1 billion years
c. 4.6 billion years
d. 10.2 billion years

i think slash and

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.