Question

multiple select question
select all that apply
which of the following can be concluded based on the diagram showing the change in the rate of photosynthesis as a function of the intensity of light under varying conditions?
□ regardless of the concentration of carbon dioxide, when light intensity is increased from 2000 foot - candles to 2500 foot - candles, the rate of photosynthesis remains unchanged
□ at all temperatures, the rate of photosynthesis remains constant at all light intensities
□ regardless of the ambient temperature, increasing light intensity always results in an increase in photosynthetic rate
□ at light intensities greater than 1500 foot - candles, higher temperature results in higher photosynthetic rate.

Explanation:

1. Analyze the graph: The graph shows the relationship between the rate of photosynthesis and light - intensity under different conditions of carbon - dioxide concentration and temperature.
2. Evaluate each option:

• For the first option: Looking at the graph, when light intensity is increased from 2000 to 2500 foot - candles for both excess CO₂ conditions (35°C and 20°C), the rate of photosynthesis remains flat, so this option is correct.
• For the second option: The graph clearly shows that the rate of photosynthesis changes with light intensity at different temperatures, so this option is incorrect.
• For the third option: At higher light intensities, the rate of photosynthesis plateaus for some conditions, so increasing light intensity does not always result in an increase in the photosynthetic rate, and this option is incorrect.
• For the fourth option: When light intensities are greater than 1500 foot - candles, for the same light intensity, the curve for 35°C (higher temperature) has a higher photosynthetic rate compared to 20°C, so this option is correct.

Answer:

First option: Regardless of the concentration of carbon dioxide, when light intensity is increased from 2000 foot - candles to 2500 foot - candles, the rate of photosynthesis remains unchanged.
Fourth option: At light intensities greater than 1500 foot - candles, higher temperature results in higher photosynthetic rate.