When Laurentia collided with Gondwana during the Alleghanian orogeny, a broad region of warped, faulted rocks formed, the remnants of which still crop out in the Appalachian and Ouachita Mountains. This broad region of deformed rocks is called

The sun's parallax would be 180 degrees, greater than which you can't get.  so a. would be your anwser 

Amath expression is a collection of one or more terms, which are separated by the signs ( + , - , x , / ).example :   8+b8+b  or  a−3a−3in algebra, an equation is a mathematical statement with two expressions where, each expression is separated by an equal (=) sign. variables can be present on both the sides of the equality (=) sign and we use letters to denote such variables.example 1:   x=4+2x=4+2  , [here, we can observe that the variable is present only on one side of the equation].example 2:   2x+3=x+42x+3=x+4  , [here, we can observe that the variables are present on both side of the equation].