In an experiment, Dr. Farouk studied houseplants that had flourished for years. Over a three-day period he spoke to the plants encouragingly. He then transplanted them outside into a garden and stopped talking to them. Although he continued watering and fertilizing the plants, they soon wilted. When they had not recovered after two days, Dr. Farouk became so concerned that he started talking to them every hour; the next day they began to recover. Which one of the following is most strongly supported by the information above? ['Watering plants too much is as hazardous to their well-being as not watering them enough.', 'Talking to plants enhances their health.', 'Changes in growing conditions can affect the flourishing of plants.', 'Plants always need at least two days to adjust to transplantation.']