There are two types of reactions in photosynthesis: light-dependent reactions and light- independent reactions. A group of biology students creates a set of devices that will automatically measure the rates of both types of reactions. The light-dependent reaction rate is tracked by the rate of water uptake in plants, and the light-independent reaction rate is tracked by the rate of carbon dioxide gas uptake in plants. The students decide to measure the rate of the light-dependent reactions at noon, when the light is brightest, in a sunny room. They measure the rate of the light-independent reactions at 8:00 p.m. in a dark room under very minimal lighting conditions. What is the most obvious critique of the students' experimental design? The light-independent reactions are dependent on the products of the light- dependent reactions which do not occur at night or under very low light conditions. The light-dependent reactions do not require water but rather carbon dioxide gas that is needed for carbon fixation. The presence of even very low light levels in the room will ensure that the light- independent reactions of photosynthesis will not happen. The rate of the light-dependent reactions will actually be greater earlier in the morning with more indirect light and milder temperatures. Ther Ther