¿Por qué se dice que el imperialismo colonial se convirtió en una necesidad para las potencias industriales a partir del último tercio del siglo XIX?

When volcanoes erupt, magma (hot, molten rock) rises toward the surface of the earth. as magma cools, solid rock forms. this rock contains substances from the interior of the earth. which of the following natural resources is likely to be plentiful near subduction zones where volcanic activity has occurred in the past?