humans have been on earth for 300000 years
earth has several_billion_human_beings earth's_year has not 365_days earth's_year has 365_days earth has not several_billion_human_beings earth is over_400_million_years_old. earth is over_5_billion_years_old. earth is 4.5_billion_years_old. world has humans_in no_human has lived_longer_than_150_years no_human has not lived_longer_than_150_years