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?