tall buildings in siberia are built 6 feet off the ground on special posts to keep the buildings a. cooler in the summerb. warmer during winterc. from thawing the ground beneath themd. safe from floods

The correct answer is - C. from thawing the ground beneath them.

Tall buildings in Siberia have to be lifted from the ground because in most of Siberia the ground is not stable. The ground in this part of the world is under the influence of the permafrost for the biggest portion of the year, which makes the ground very rich with frozen water, but unlike the popular opinion that in Siberia the summers are cold too, they are actually not cold but pretty warm and temperatures can reach up to 30 C degrees. This warmth makes the ice and snow melt, thus making the ground very unstable and very rich with water, so any higher and heavier building will start sinking into it, and after that when the winter strikes again the lower part of the building will be trapped by the permafrost.

Mexico has a host of environmental problems, including significant chemicalpollution  from factory discharges and waste dumping, but the main threat to itsbiodiversity  probably stems from  deforestation  and other natural habitat losses. forest habitat is lost for a number of reasons