A plant uses carbon dioxide and water to form food and oxygen. Why is this a chemical change? A. The mass of the plant increases greatly.

B. The properties of water and food are same.

C. The plant increases in height as food is produced.

D. The properties of carbon dioxide and oxygen are different.

With the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 1.90