A hiatal hernia does not cause many symptoms by itself, but when a sliding hernia occurs, the abnormal location of the gastroesophageal (GE) junction above the diaphragm affects its function and stomach contents can reflux into the esophagus.
-You need to work on sentence structuring. For example, when you wrote, The immigration, as a decision maked by a person is an act that occurs, because of some factors especially in the under developed countries and the most importants causes or reasons are mainly social reasons, politic reasons and economic reasons..
Illegal immigration is the migration of people across national borders in a way that violates the immigration laws of the destination country. Some countries have millions of illegal immigrants. Immigration, including illegal immigration, is overwhelmingly upward, from a poorer to a richer country. However, it is also noted that illegal immigrants tend not to be the poorest within their populations.