If the dry bulb is 80, and the wet bulb is 70 what is the relative humidity

What first caused people to consider that the continents were once one large landmass?

As water is cooled from 4 c to 0 c its density

Mexico city is an example of how humans alter their environment because it was a. one of the world’s largest cities b. built on drained and filled lake beds c. built after conquest by the spanish d. once the capital of the aztec empire