The fall of Rome began with poor leadership, attack by invaders and ?

Poor economy

Explanation:

The decline of Rome started in the 3rd Century, but then there was a welfare during Constantine and Diocletian. Still, after the Empire was divided in 395 it was impossible to preserve the independence of the Western Empire. There wasn't enough resources and money to pay the army, so the mercenaries turned against country. It was just a question of the time when the Empire will collapse and that finally happened in 476.

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.

ww1 weapons: tank. tanks were used for the first time in the first world war at the battle of the somme. they were developed to cope with the conditions on the western front. the first tank was called 'little willie' and needed a crew of 3.