Answer:

ARTICLEI

AnswerCrossword Clue
ARTICLEIConstitution's begining
ARTICLEIIt gives Congress tax-collecting power
ARTICLEIIt established a bicameral legislature
ARTICLEIConstitution section on Congress' powers
ARTICLEIWhere to find the elastic clause
ARTICLEIPreamble follower
ARTICLEIIt contains the elastic clause
ARTICLEIIt contains the three-fifths clause
ARTICLEIIt gives Congress the power to declare war
ARTICLEIFirst main part of the Constitution
ARTICLEIFirst main Constitution part
ARTICLEIFirst Constitution section