Which of the following statements about net primary productivity is true?
a) Equatorial regions support modest levels of net primary productivity.
b) Net primary productivity in an ecosystem is primarily a function of temperature and precipitation. Nutrient levels have little effect.
c) Water demand to an ecosystem is a function of both incoming solar radiation and temperature.
d) Actual evaporation measures the supply and demand for water to an ecosystem.
e) Net primary productivity is lower along coastlines than in the interior regions of continents.