What does 69 mean? Give me the correct answer please

Remote sensing of the earth's surface and atmosphere may involve the use of what type of instruments?

What are the two main purposes of edgar allen poe’s, “the masque of the red death? ”

Cartels control the production and pricing of goods mainly through a) the elimination of competition. b) the cooperation of their members. c) the limitation of price controls. d) the manipulation of government pressure.