Which of the following natural processes involve the use and renewal of atmospheric gases?
a.
decaying of organic matter
b.
condensation of water vapor into precipitation
c.
evaporation of surface water by the sun
d.
all of these

Draw the farm's ppf for corn and beef. draw a point that shows an inefficient combination of corn and beef. label ita. draw a point that shows an unattainable combination of corn and beef. label itb. draw a point that shows an efficient combination of corn and beef. label itc.