Final answer:
A constitutional assembly was established when rapid agreement on a constitution couldn't be reached, acknowledging the need for a stronger central government than what the Articles of Confederation provided, leading to the U.S. Constitution with a bicameral legislature.
Step-by-step explanation:
When it became clear that rapid agreement on a constitution would not be reached, a constitutional assembly was established to address changes in the government. However, the Articles of Confederation were inadequate as they created a government powerless in most areas, lacking the means to enforce laws, levy taxes, or raise a national military effectively. The challenges under the Articles highlighted their inefficacy and prompted the Constitutional Convention of 1787, which acknowledged the need for a stronger central government and led to the drafting of the U.S. Constitution, setting up a bicameral legislature akin to the British Parliament but with a greater balance of power among the three government branches.