Photosynthesis drives the change from S to T

Steps:

• Identify the change between points S and T, such as an increase in oxygen or biomass on a graph.
• Recall that photosynthesis converts light energy into chemical energy, producing oxygen and glucose.
• Match the observed increase to the output of photosynthesis in light conditions.
• Eliminate processes that do not produce such gains.

Why B is correct:

• Photosynthesis follows the equation 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂, directly causing rises in oxygen or sugar levels under light.

Why the others are wrong:

• A. Osmosis moves water across membranes but does not produce gases or biomass changes.
• C. Respiration consumes oxygen and glucose, decreasing levels opposite to the change.
• D. Transpiration causes water loss from leaves but does not alter oxygen or carbon compounds.

Final answer: B