An agricultural scientist investigated the rate of photosynthesis in spinach (Spinacia oleracea) cultivars grown in a hydroponic vertical farming facility under various light intensities. The experimental results collected were as follows:
Which range of light intensities caused the rate of photosynthesis to change the most?
Explain the change in the rate of photosynthesis when the light intensity increased from 0 to 60 a.u.60\text{ a.u.}60 a.u.
A commercial grower decided not to use a supplemental light intensity higher than 75 a.u.75\text{ a.u.}75 a.u. to grow the spinach plants. Suggest two reasons for this decision.