Digital ACT Science Practice Question #1808

Why does elevated CO2 (800 and 1,200 ppm) eliminate the high-temperature photosynthetic decline at 35°C? Experiment Context (Photosynthetic Rate under Carbon Dioxide Enrichment): Agricultural scientists monitored the net carbon assimilation rate (umol CO2 / m^2 * s) of soybean leaves across three atmospheric CO2 concentrations under identical high-light conditions (1,500 umol photons / m^2 * s): Table 18: - Ambient CO2 (400 ppm): Leaf Temp 25°C = 26 umol/m^2*s; Leaf Temp 35°C = 22 umol/m^2*s - Elevated CO2 (800 ppm): Leaf Temp 25°C = 38 umol/m^2*s; Leaf Temp 35°C = 41 umol/m^2*s - Hyper-Elevated CO2 (1,200 ppm): Leaf Temp 25°C = 44 umol/m^2*s; Leaf Temp 35°C = 49 umol/m^2*s