When grant broke the confederate lines during the siege of petersburg, lee a. alerted president davis to evacuate richmond. b. fled with his army to savannah. c. surrendered immediately to grant. d. gathered his remaining troops for one last stand.

A. alerted President Davis to evacuate Richmond.

Explanation:

When General Robert E. Lee discovered Grant had broken the Confederate lines during the siege of Petersburg, he informed Confederate President Jefferson Davis that he had to evacuate Richmond and Petersburg to go to Danville. Davis promptly made the necessary arrangements to assure the evacuation of Richmond that same night through the Richmond and Danville Railroad.

to act quickly in times of danger to the united states

because you have to act quickly if you want to live/survive.

congress also has implied powers, which derive from the necessary and proper clause of the constitution and permit congress "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.