sentences: the earth 's atmosphere is made of 23133 percent oxygen by mass
docs: composition_of_earth is 28_percent_oxygen. oxygen is gas_at_1_atmosphere. earth has atmosphere earth is 35_percent_iron. composition_of_earth is 0.4_percent_aluminum. composition_of_earth is 17_percent_magnesium. composition_of_earth is 35_percent_iron. composition_of_earth is 13_percent_silicon. earth's_atmosphere has oxygen composition_of_earth is 0.6_percent_calcium.