In philosophy, substance means, approximately, that element of an object without which it would not exist. In the millennia-old Aristotelian tradition[?], as well as early modern[?] traditions that follow it, substances are treated as having attributes[?] and modes[?].
... 18 to 24, 29.0% from 25 to 44, 24.2% from 45 to 64, and 12.7% who are 65 years of age or older. The median age is 39 years. For every 100 females there are 104.2 males. ...