DENDROLOGY

Detailed explanation-1: -In daylight, plants are both respiring and photosynthesising, so oxygen and carbon dioxide are diffusing in and out of the leaves. But overnight, without sunlight, photosynthesis stops and stomata close. With just respiration taking place, only oxygen diffuses into the leaves and only carbon dioxide diffuses out.

Detailed explanation-2: -When we breathe out, we release carbon dioxide into the air which is then used by the plants to make their food and the cycle starts all over again. This system is called the oxygen cycle.

Detailed explanation-3: -Plants do require oxygen for respiration which in return gives out carbon dioxide. Unlike animals, plants do not have any specialized structures for gaseous exchange but they have stomata (present in leaves) and lenticels (present in stems) which are involved in the exchange of gases.