Which plays the most important role in the movement of water through a plant – the absorption of water by the roots or the evaporation of water from the leaves?

the absorption of water by the roots

Explanation:

Evaporation of water through the leaves is known as transpiration, and it occurs readily only when environmental conditions such as humidity is high.

On the other hand, the absorption of water by root hairs which is then conducted by the xylem vessels up the stem to various parts of the plant is a important process that determines how water move through a plant to ensure cellular processes such as photosynthesis, respiration etc takes place.

Thus, the absorption of water by the roots plays a much more important role in the movement of water in a plant

not too sure but maybe in the hot springs.

that is wrong, its not thymus.