The image is a photograph of a wooden sign with Chinese characters written on it. The sign is titled "Natural Thermostat" and has a thermometer on the right side. Below the thermometer, there is a question that reads "There are four seasons in a year: spring, summer, autumn, and winter. How do seeds know when the season is right for germination?" The text is written in both Chinese and English. The background of the sign is a light beige color.