The two words at the top of a dictionary page showing the first and last words on the page are called

The answer is: guide word.

In any reference work presented in alphabetical order —like a dictionary—, at the header or top of the page there are two terms that refer to the first and last words contained in the page. This is an invaluable aid for whoever uses the reference material to make his or her search faster and more efficient.

answer; /// the correct answer to the above statement is (a) because of the decline on native american labor forces;