The united nations approach crimes very good and calm they put the criminal in jail to prevent it and make them learn a lesson.
The sand is primarily derived from weathering of Cretaceous sandstones in North Africa. When these sandstones were deposited in the Cretaceous, the area where they are now was a shallow sea. The original source of the sand was the large mountain ranges that still exist in the central part of the Sahara. These mountains are volcanic and intrusive, and the granite rock weathers out to leave behind quartz sand grains that are carried by rivers to the sea. These sand deposits eventually formed into sandstone, and as they were uplifted began to weather and break down into sand again.
Only about 10% of the Sahara is actually covered by sand, and parts of the Sahara are in fact covered by soil. More than half of the area comprises soils known as yermosols, with shallow profiles over gravel or pebble beds. These soils have been developing over the past 50 million years.
The right answer is : a, sorry for the mistake
Migration is moving to another country to permanently or semi-permanently stay there. It is one of the main causes of population change. The basic principle is when you move from country A to country B, country A loses one citizen and country B gains one. Due to economic and political reasons, the rate of migration is increasing. On one hand, migration can help increase the human resources of countries lacking it. It can help balance population between countries. On another, mass migration can cause economic problems. Currently, Europe is facing major crisis in catering immigrants from Syria and other countries.