Nick is researching why baking powder is a common baking ingredient. he learns that baking powder contains tartaric acid and sodium hydrogen carbonate. he also learns that when water is added to cake ingredients, a reaction occurs. it causes bubbles to form that make the cake rise. what gas is in the bubbles, and why do they form? a. carbon dioxide gas forms because an acid and a carbonate react. b. carbon dioxide gas forms because an acid and a base react. c. hydrogen gas forms because an acid and a metal react. d. hydrogen gas forms because an acid and a base react.

12) several teeth were found in an area of flat land covered with trees and plants. the teeth were examined by a paleontologist, and it was determined that the teeth came from a shark. they found many other shark teeth in this area. however, the people who discovered the teeth were puzzled, because there was no source of water near where the fossils were found. what is the paleontologist's best explanation for why the teeth were found in this area? a) sharks used to live on flat land. b) this area was once covered with salt water. c) this area was once covered with freshwater. d) someone buried the shark teeth deep in the ground.