Geology

[PussyCat]

Probably the most useful science that encompasses every other science, math, and engineering. Without it the water you drink would kill you or not be there (groundwater aquifers), the buildings we use would [subside]/crack/soil [compress]/liquefy/corrode/fail, just about anything wouldnt exist (what do you think steal, iron, copper, titanium, etc. are mined from?), there wouldnt be oil, [natural gas], or coal (the world would stop), we would still think the Earth was 6000 years old, the environment would die, and a bunch of other things you wouldnt even think of would cease.

[Sommer]

the study of the rocks and similar substances that make up the earths surface:

[Monty]

The science that deals with the earths physical structure and substance, its history, and the processes that act on it.