What happens to relative humidity of an unsaturated parcel of air when the temperature decreases?

What is the difference between external & internal migration

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

Horizon a is also sometimes called a. topsoil b. subsoil c. bedrock d. weathered bedrock