Which of these is used to make the dough rise and give it porous structure?

In cooking, a leavening agent or raising agent, also called a leaven or leavener, is any one of a number of substances used in doughs and batters that cause a foaming action (gas bubbles) that lightens and softens the mixture. An alternative or supplement to leavening agents is mechanical action by which air is incorporated. Leavening agents can be biological or synthetic chemical compounds. The gas produced is often carbon dioxide, or occasionally hydrogen.

When a dough or batter is mixed, the starch in the flour and the water in the dough form a matrix. The starch then gelatinizes and sets, leaving gas bubbles that remain.

Chemical leavening using pearl ash as a leavening agent was mentioned by Amelia Simmons in her "American Cookery", published in 1796.