Digital ACT Science Practice Question #1820

The dramatic reduction in transpiration during Condition 4 (Total Darkness) is best explained by: Experiment Context (Foliar Transpiration under Environmental Variables): Biologists measured water loss (mL/hr per m^2 of leaf area) from potted sunflower plants in controlled environmental chambers over 4-hour test periods: Table 22: - Baseline (22°C, 50% humidity, calm air): Transpiration = 45 mL/hr*m^2 - Condition 1: High Humidity (85% humidity, calm air): Transpiration = 18 mL/hr*m^2 - Condition 2: Elevated Wind (50% humidity, 5 m/s fan): Transpiration = 82 mL/hr*m^2 - Condition 3: Elevated Temp (35°C, 50% humidity, calm air): Transpiration = 76 mL/hr*m^2 - Condition 4: Total Darkness (22°C, 50% humidity, calm air): Transpiration = 6 mL/hr*m^2