The toba supervolcanic event caused a bottleneck in the human population by
a. raising global temperatures
b. humans choking on volcanic ash
c. inducing an ice age
d. volcanic lava burning human villages

So, the bottleneck is not very directly connected to the event: so people didn't die instantly by chocking or lava - we can reject answer b) and d).

The Toba supervolcanic event did not raise global temperatures - quite the opposite is true, the global climate went through a time of cool-down,

The correct answer is c. inducing an ice age

Humans have survived and thrived in mexico city by using technology to create greater access to land. when the spanish conquered the aztec capital, tenochtitlan, in the 16th century, they built mexico city by draining the lakes and filling in the lake water to create more arable land for agriculture. this technique of land reclamation has continued to be fundamental to human civilization in mexico city. 

There is a great difference between the windward and leeward side of a mountain. windward and leeward sides are opposites.