sentence: We limit the number of houses and the number of people living in those houses , because more people would mean we have to clear vast expanses of land for housing , which would mean a reduction in the number of trees and a deathblow to the natural balance .
modified: We limit the number of houses and the number of people living in those houses because more people would mean we have to clear vast expanses of land for housing which would mean a reduction in the number of trees and a deathblow to the natural balance .
transformation: PUNCT, PUNCT