Read the sentences. Antarctica is a continent that is vastly underused. Filled with resources ranging from fish to minerals to oil, we are overlooking valuable opportunities for our nation's economy. What is the effect of the word vastly on the author's purpose?

It emphasizes the author's argument that Antarctica is not being explored nearly enough

The effect of the word vastly on the author's purpose is that of making the readers understand that such an extent of land and opportunities should not be ignored. He emphasises the meaning of the adjective by making use of an adverb that refers to many different things. The great proportion of land, all its untouched resources and the enormous gain this wuold have if properly used.