The null hypothesis, which demonstrates that evolution is not occurring from generation to generation, is known as the model.

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.

other quantities, called derived quantities, are defined in terms of the seven base quantities via a system of quantity equations. the si derived unitsfor these derived quantities are obtained from these equations and the seven si base units.