Answer:
During winter time when the sunlight decreases the rate if photosynthesis also decreases in the plant as the sun is the major source of energy for the plant and it leads to produce less glucose.
The plant produces food through a process called photosynthesis this photosynthesis happens through employing the light energy got from sunlight. Only 10 % of the sunlight is trapped by the organisms, if the sunlight further decreases it would not have any sufficient energy to carry out photosynthesis effectively.