What were the powers of Congress that were limited in this excerpt of Article IX?

How would having more railroad tracks be advantageous during a war

The two-factor theory of emotion was proposed by

Which best describes the purpose of the south carolina exposition and protest, which was written by john c. calhoun? a) to explain why the south was nullifying the tariff of 1828 b) to describe the ways the tariff of 1828 would southerners c) to persuade northern states to rebel against the federal government d) to ask england for if the south decided to secede from the union