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.
... 209 families residing in the village. The population density is 105.9/km² (274.2/mi²). There are 578 housing units at an average density of 82.3/km² ...