HORTICULTURE

Detailed explanation-1: -Thus, the correct answer is light duration.

Detailed explanation-2: -The main factors affecting rate of photosynthesis are light intensity, carbon dioxide concentration and temperature.

Detailed explanation-3: -Duration: The longer the plant is exposed to light, the longer the process of photosynthesis will continue. As long as the temperature of the plant remains balanced, photosynthesis will occur.

Detailed explanation-4: -The rate of photosynthesis is directly proportional to the light intensity until another factor becomes limiting. At very high light intensities, photosynthesis is slowed, but these light intensities do not occur in nature.