Many systems and technologies have been designed to communicate over long distances. They all send information that has been encoded into a signal. What must a receiver be able to do to understand a signal that is being sent to them?

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.