The yeast will produce the most cellular respiration at an optimum temperature. This temperature will be at a normal room temperature. If the temperature of the environment surrounding the yeast is too low, the rate will decrease, because the molecules involved in the process of cellular respiration will slow down resulting in lesser rate. In addition, if the temperature of the environment surrounding the yeast is too great, the rate will also decrease, because the enzymes involved in cellular respiration will denature causing the rate to decrease. Therefore, the yeast will have the greatest rate of cellular respiration at room temperature.