The revolution grew more violent mainly because radicals reacted to

The revolution grew more violent mainly because radicals reacted to the National Assembly falling apart.

Rumors of foreign interference to end the revolution is the right answer.

Explanation:

It was rumored that Louis XVI, the King of France had entered into confidential colloquies with the rulers of Prussia and Austria to uproot the revolution. It infuriated the rebels and hence National Assembly announced war against the Prussia, Austria and against Louis XVI and his followers. Anyone suspicious of resisting the Revolution was guillotined and executed. Accordingly, the Revolution grew more and more vehement.

is this like a kind of true or false question?

the viking voyages took place during the middle ages, which was about this time. 500 to 1350. the viking voyages took place during the middle ages, which was about this time.