Which branch of biology is concerned with the naming and classifying of organisms?

Transpiration.

Explanation:

Transpiration is the answer, because transpiration is a plant’s loss of water, mainly through the stomates of leaves. Stomatal openings are necessary to admit carbon dioxide to the leaf interior and to allow oxygen to escape during photosynthesis, hence transpiration is generally considered to be merely an unavoidable phenomenon that accompanies the real functions of the stomates.

( A brief explanation)

Credits to:

https://www.britannica.com/science/transpiration