Some volcanoes form above an especially hot column of magma known as a

hot spot

Explanation:

Some volcanos form above an especially hot column of magma. This column is called a HOT SPOT. A hot spot supplies a steady flow of magma that rises to the surface. As a plate moves slowly over a hot spot, volcanoes form in new locations. Eventually, a hot spot can produce a CHAIN OF VOLCANOES.

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no , per capita income is not a true measure of the development because: -it only tells us about average income not how income is distributed among the people.it only give us an idea of the economic aspect.it is only at the qualitative basis.moreover, income is not only the way of development other factors are also as much as important as income.

i honestly have no idea