The constitutional convention created a house of representatives as a part of the

great compromise.
three-fifths compromise.
unicameral compromise.
commerce and slave trade compromise

The correct option is A.
All the states in United States of America are not equal in term of the number of people that live in them. The great compromise is an agreement between the small and the big states, which determines the number of representatives that each state will have under the US constitution and in legislature. 

From mexican american war , us gained new mexico.

Very useful. it is to learn because history repeats itself so learning about it those mistakes not happen again.