This book is dedicated to each teacher; who with care, effort, patience and passion every day seeks to teach students in their country in a better way. After all, students are the future of our countries, and that future lies on the hands of our teachers. Because education is the path to a better life and the key to the development of each country in every way; teaching is the profession of professions, and teachers are trainers and guides for future professionals in every field of life in each country. God bless teachers! Lic. Mauro Mackay S.