Most magma forms from a) the partial melting of solid rock in the crust or upper mantle b) the friction of the crust colliding with lithosphere slabs c) the solidifying of rock in the crust or upper mantle

The answer is A) the partial melting of solid rock in the crust or upper mantle

Iam pretty sure it is answer c. meep i hope you have a great day ^^

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].