Identify and explain two constitutional principles that allow government to be flexible

Two constitutional principles that allow government to be flexible are
1) Federalism and devolution 
2) Elastic Clause

Federalism makes the government flexible by dividing the responsibilities and balancing the power between federal government state and local government through the process of devolution.
Elastic Clause allows the congress to make those laws which specifically are not mentioned in the constitution and this all allows the flexibility of the government. 

idk

which sentences ? that question is incomplete