A caldera viscous or acidic lava plugs the vent of a volcano this leads to violent eruptions this causes the crater to be blown off the top of the volcano subsides or collapes forming a basin shaped depression.called a caldera .hope this helps
D tornados. tornados have to do with warm and cold fronts of air coming in contact with each other.
I know that question #4 is B.) Sun
If a country is isolated, it will have to produce everything that it needs: especially food clothes and medicine. It won't be able to specialize, but it will have to focus on satisfying the needs of the people.
If it is not isolated, it can specialize in the things that it can produce the best and fastest, and hope to exchange it for the things that it can't produce.
