What is the best thing to do to prevent hairs to fall? and what can we do for them to grow back?

Stay healthy: The best way to grow hair naturally is to stay healthy: regular exercises and eating a well-balanced diet to provide your body with the necessary nutrients to support growth and repair. Artificially grown hair such as that by use of rogaine (minoxidil) etc...Is not a lasting and healthy effect. Stimulate/massage your scalp regularly to keep a good blood supply. There isn't much else you can do. Good luck.