Which term identifies the dark smooth areas on surface of the moon

The dark smooth areas on the surface of the moon is called Maria.

Maria is made up of solidified lava which is a result of volcanic activity on the moon.

When Galileo observed these smooth dark spots on the moon he called them 'mare' which is latin for 'sea'. And the plural form of mare is 'maria'. Unlike Galileo predictions, recent investigations confirm that maria are not oceans but solidified lava.

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.