The feature is called Evolution based on hypothesis. Charles Darwin's Hunting hypothesis was that Bipedalism freed the hands for making tools. Rodman and McHenry's patchy Forest Hypothesis, bipedalism was ore efficient than quadrupedalism such that forests diminished and food resources also became scattered. Also not valid because bipedalism evolved in a forest environment. Owen Lovejoy's Provisioning Hypothesis that males assist females more efficiently in procuring food; the need for food hypo, Birth spacing would be reduced.
The residents can carpool from place to place, bike, or walk, which significantly reduces fumes. They can also grill less, and have fewer fires in their fireplaces.
