That's because Kepler-186f orbits a red star, and we're just speculating that perhaps the plants there, if there is vegetation that does photosynthesis, it has different pigments and looks red.
这是因为开普勒-186f围绕着 一颗红色的恒星运行， 我们只是猜测那上面的植物， 假设有可以进行光合作用的植物， 那些植物就会含有不同的色素， 让它们看起来是红色。