The most common type of mechanical weathering occurs when

a.
acidic water seeps into a crack in a rock.
b.
seeds take root in a crack in a rock.
c.
water freezes in a crack in a rock.
d.
rocks collide during subduction.

The correct answer is c. water freezes in a crack in a rock.

The water freezes which makes its volume greater so it breaks the rock so then the water thaws and then new water comes, even more of it, so it freezes, and so on and so forth until the rock breaks completely.

Ithink it is space that makes up 70 percent

The peak above is part of the  sierra madre occidentals ,  a chain of volcanic mountains that runs through the middle of central america.