A leavening agent is an organism or substance that when added to a dough[?] of flour and water causes it to "rise" by evolving carbon dioxide or other gasses that become trapped as bubbles[?] within the dough.
... out with 13.8% under the age of 18, 34.0% from 18 to 24, 17.6% from 25 to 44, 20.5% from 45 to 64, and 14.1% who are 65 years of age or older. The median age is 28 years. ...