Answer: The Necessary and Proper Clause gave it relevance and the amendment process gave it flexibility.
Explanation:
The United States of America consist about seven thousands words. The "Necessary and Proper" Clause can be found in Article 1 on the right section of the constitution. The article states and I quote:
''...to make all Laws which shall be NECESSARY AND PROPER for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or any Department or Officer thereof".
NOTE: The words in block/capital letters identify the clause.
The Necessary and proper clause is also reffered to as an Elastic clause.
Also, the Amendment process makes the constitution flexible. The constitution can be amended if the majority (two-thirds) votes for an amendment in the constitution.
characteristic of the Constitution has kept it relevant and flexible, by virtue of very general language is the NECESSARY AND PROPER CLAUSE.