Why Plants cannot make their food at night?
Plants, like all living organisms, require energy to survive and grow. They obtain this energy through the process of photosynthesis, which is the conversion of sunlight into chemical energy. However, plants are unable to carry out photosynthesis at night for several reasons.

Lack of sunlight
One of the main reasons plants cannot make their food at night is the lack of sunlight. Photosynthesis requires light energy to power the chemical reactions that convert carbon dioxide and water into glucose and oxygen. Without sunlight, plants are unable to produce the energy they need to survive.

Dependency on chlorophyll
Another reason plants cannot make their food at night is that photosynthesis relies on the presence of chlorophyll, a pigment found in the chloroplasts of plant cells. Chlorophyll absorbs sunlight and uses it to drive the chemical reactions of photosynthesis. Since there is no sunlight at night, chlorophyll cannot perform its function, and photosynthesis cannot occur.

Storage of energy
Plants have adapted to this limitation by storing energy in the form of starch during the day when photosynthesis is active. This stored energy is then used at night to fuel essential processes like respiration, which allows the plant to continue growing and functioning even in the absence of sunlight.

Conclusion
In conclusion, plants cannot make their food at night because photosynthesis requires sunlight and chlorophyll, both of which are unavailable during the night. However, plants have evolved mechanisms to store energy during the day, allowing them to survive and grow even when photosynthesis is not possible.