how do non green plants prepare food?
Leaves of plants are green in colour due to the presence of pigment chlorophyll. This pigment is responsible for carrying out photosynthesis in plants. In some plants, leaves are orange or yellow in colour it doesn't mean that they do not contain chlorophyll. It shows that such leaves contain other pigments in higher amount than chlorophyll. But such plants are capable of carrying out photosynthesis.
Some other plants that are non green can follow parasitic mode of nutrition.