Task: Text Categorization
Input (English): This material loses effectiveness after an action called girdling, which leads to tissue death. Ernst Munch proposed that this material works via the pressure flow hypothesis. This material consists of parenchymal, sieve-tube, and companion cells. In trees, this material is found in the inner bark, which is why its name derives from the Greek for ""bark. "" (*) For 10 points, name this living vascular material that transports nutrients within a plant, contrasted with the water-carrying xylem.
Output (English): Science