A student grows identical plants in sunlight and in complete darkness for 2 weeks. Which statement best explains the difference in plant growth between the two groups?

Students place Elodea plants in water under different light intensities and count bubbles released in 5 minutes as a measure of photosynthesis.

Students compare tomato plants grown under natural sunlight and LED grow lights.

Students place pond algae in three water baths at 10 °C, 25 °C, and 40 °C under identical light and CO₂ conditions.

Part A: Students investigate which factors increase or decrease photosynthesis in plants. Categorize each factor below.

Part B: With light and CO₂ held constant, explain why photosynthesis slows under the conditions you categorized in Part A.