Which statement best describes evidence that a chemical reaction occurs as a cake bakes?

Question: Which statement best describes evidence that a chemical reaction occurs as a cake bakes?

(A). The water in the cake batter evaporates. 

(B). The cake takes the shape of container it is baked.

(C). The water in the cake batter is used to keep the cake moist as it bakes.

(D). The cake rises as gas from in the baking cake. 

The correct answer is (D). The cake rises as gas from in the baking cake. This is evidence that a chemical reaction occurs as a cake bakes because the gas is a new product that is formed from the reactants in the batter. The other statements are not evidence of a chemical reaction because they do not involve the formation of new products. The water in the cake batter evaporates (A) and is used to keep the cake moist as it bakes (C) are physical changes that do not alter the identity of the substances. The cake takes the shape of container it is baked (B) is also a physical change that depends on the external force applied to the batter.