Why are the three river systems (Indus, Ganges, Brahmaputra) a key to life in South Asia?

They carry fertile soil to floodplains allowing agriculture
They provide water for the mountains
They the major food system for South Asia

The answer is b or dmost likely bhope it

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].

Answer volcanic outgassing;

Answerbeaches;