Photosynthesis rate saturates at high light intensity

Steps:

• Identify the experiment as measuring oxygen production from photosynthesis, where light is a key factor.
• Recall that low light limits the rate, so increasing intensity boosts gas volume proportionally at first.
• Note that beyond a threshold, other factors (e.g., CO2) limit the rate, causing volume to plateau.
• Conclude the graph shows initial rise followed by leveling off as intensity increases.

Why C is correct:

• C depicts a curve rising steeply then flattening, matching the limiting factor law in photosynthesis where rate saturates when light is non-limiting.

Why the others are wrong:

• A shows linear increase, ignoring saturation.
• B shows exponential rise, unrealistic as rates don't accelerate indefinitely.
• D shows decrease or no change, contradicting light's positive effect.

Final answer: C