What is a constant in a science experiment?

What are chlorofluorocarbons made of

What is the difference between an igneous, sedimentary and metamorphic rock

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.