<span>the best option is B
the development of more efficient agriculture
The emergence of efficient forms of agriculture especially in Mesopotamia, led to emergence of early city states as food was produced in surplus to feed the town population. it also led to division of labor. this form of agriculture also contributed to sedentary lifestyle and improved nutrition thus explosive population that contributed to city establishments.
</span>
The answer fam is........ A minimum of (Nine)
states had to ratify the US Constitution for it to go into effect.
on September 28, Congress directed the state legislatures to call ratification conventions in each state. Article VII stipulated that nine states had to ratify the Constitution for it to go into effect.
The above system of United States Constitution is showing three organs of the state i.e Legislative branch, Executive branch and the Judicial branch.
And below each division, their works are given. Aswecan were that, each of the organ is at same height which shows that they are practicing equal powers and they don't interrupt in each others work.
They practice the system of <u>Checks</u><u> </u><u>and</u><u> </u><u>Balances</u> to ensure that none of the organ is enjoying and grabbing too much.
So, the most appropriate option is:

Checks and balances system.
And, we are done !!
#CarryOnLearning...
<u>━━━━━━━━━━━━━━━━━━━━</u>