This question will be answered based on general photosynthetic understanding. The answer is:
The production of oxygen would increase
Explanation:
The characteristics of most plant forms is their ability to photosynthesize i.e. use solar energy (from sunlight) to make food (chemical energy). The product of this photosynthetic process is OXYGEN gas, which is released as a waste product via the stomata on their leaves. Note that, photosynthesis cannot occur without LIGHT as it provides the energy needed for the process.
Hence, in the duckweed plant like every other photosynthetic plant, the increase in the intensity and duration of exposure to light means the rate at which photosynthesis occurs will be increased. An increased photosynthetic rate means the synthesis of the products will also be increased i.e. glucose and OXYGEN.
