If is added to the single cell model of global circulation, the single cell convection system becomes a three cell convection system. A, Earth rotation
B. differential heating between land and water
C. the pressure gradient force
D. Earth axis tilt

Dall of the above all of the choices make sense

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].

Answerhave flowing water either episodically or during only a portion of the year;