A researcher is maintaining Coleus plants in a temperature- and light-controlled growth chamber that gets no outside light. The researcher must maintain the health of the plants but does not want the plants to grow much larger over time. The researcher is going to grow the plants at 30 °C and a light intensity setting of 4. The researcher wants to calculate the minimum number of hours of light at setting 4 that are needed so that the consumption of sugar and oxygen (°2) by respiration will not exceed the production of sugar and oxygen by photosynthesis. The average rate of O2 consumption by respiration in these plants at 30 °C is 2.50 mL/hour. The average rate of O2 production by photosynthesis in these plants at 30 °C and light setting 4 is 17.25 mL/hour (this value is total O, output not counting what is used by the plants in respiration). For how long should the researcher expose the plants to light each day to maintain plant health without causing further growth?