The answer would be b) push factors
How we suppose to know Read the book
The answer is the option B) hydrosphere.The prefix hydro means water and
so the name hydrosphere is the term used to refer to all the bodies of
water in the Earth, including oceans, groundwater and
glaciers.Atmosphere refers to the gas layer, biosphere to the regions
where there is life and geosphere refers to all the layers in Earth.
