Water absorbed by the roots moves through the stem and enters the leaves. Most of this water is lost in transpiration. Explain how the internal structure of leaves results in the loss of large quantities of water in transpiration​

In plants, the transpiration stream is the uninterrupted stream of water and solutes which is taken up by the roots and transported via the xylem to the leaves where it evaporates into the air/apoplast-interface of the substomatal cavity. It is driven by capillary action and in some plants by root pressure.

The answer is observations and interpreting.