Designating additional land as national parks
B.
<span>to carry out the laws passed by Congress</span>
The production of steel was entirely crucial to the development of railroads, since the rail lines themselves were made of steel, without which the trains would not be able to move.
Southern slaveholders did not want the Congress to take the power over, so slave trade while controlling foreign affairs. So they only let the Congress have power over trade, excluding slave trade, for next twenty years.
