3. Sydney, Australia, is in the Southern Hemisphere. Which choice describes the conditions there on or around December 21?
a. Summer begins.
b. Winter begins.
c. Spring begins.
d. Autumn begins

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