Baking powder is primarily used as a leavening agent in baked goods and products. It is a combination of cornstarch, cream of tartar and baking soda. The main observation that suggests that it is a mixture of substances is that fact that it produces a gas which facilitates the rising of the baked goods.
A thimble is the correct answer
Correct answer is A. Recreation center
Surface runoff happens when, usually a liquid, flows from a high point to a low point because of a driving force in pressure difference as evident in the difference in elevation. In other words, liquid will runoff from the mountains to the plains. Since a low, flat plain has no difference in elevation, it will not cause the fluid to flow. Thus, it is impossible for surface runoff to happen within a low, flat plain.