What are the basic concept of volcanoes

Hey.. A volcano is an opening in the earth's crust through which lava, volcanic ash, and gases escape. Beneath a volcano, liquid magma containing dissolved gases rises through cracks in the Earth's crust. As the magma rises, pressure decreases, allowing the gases to form bubbles

Answer mauritania is in the northwestern part of african, meaning its in the western hemisphere, and how do i know/ the map showed me so; ///: )

The scientist can conclude that there is a decrease in the natural resources due to human activities. because of innovation and modernization of the environment, then there goes pollution and other bad effects that destroys the natural resources.