Answer:
To maintain its turgor.
Step-by-step explanation:
The plant you put in freshwater stay fresh because the plant maintain its turgidity. Plants used water in the process of photosynthesis for making their own food as well as maintain its turgidity. Every cell needs specific amount of water to remain turgor, if the water is lost from the cell or plant, the plant becomes wilted so that's why by putting the plant in freshwater remain fresh.