The correct answer is option 1: Leaves.

In plants, the process of respiration involves the exchange of gases, specifically oxygen and carbon dioxide. Just like animals have lungs to facilitate this exchange, plants have specialized structures called stomata that are primarily present in their leaves. Stomata are tiny openings on the surface of the leaf that allow for the exchange of gases between the plant and the surrounding environment.

During photosynthesis, plants take in carbon dioxide and release oxygen. Conversely, during respiration, plants take in oxygen and release carbon dioxide. The stomata in the leaves help in this exchange by allowing carbon dioxide to enter the plant and oxygen to exit. Additionally, the large surface area of the leaves enables maximum gas exchange.

Therefore, the lungs of a plant can be considered as its leaves.