It is like a animal migrating because it is like hibernating because it doesn't get any food or water in winter.
The answer in this question is known as antisepsis. Antisepsis is the chemical agents that is used directly on exposed body surfaces to destroy or inhibit vegetative pathogens. Antisepsis is defined as the practice of using antiseptic to eliminate the micro-organism who causes of having a disease.
Sun and water mostly for a cycle of photosynthesis
