The central plateau contains most of mexico’s population because this region has
a.) close connections with the united states
b.) a lower risk of earthquake than anywhere else in the country
c.) large deposits of petroleum and other natural resources
d.) the country’s best farmland and pleasant, mild climate

The answers is 
D.) the country's best farmland and pleasant, mild climate

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].