What had to happen for mail service to grow?

the correct answer is individualism and exchange. at this stage, children begin to question the rules, because they can see that there is more than one side to them. different individuals have different viewpoints. they won't be able to reach this stage because of ignorance, a lack of ethics or personal biases. that is because people with that characteristiscs are not able to distinguish what is good or what is bad and they can't pursue their individual interests.

the correct answer is the following is a list of inventions made in the medieval islamic world, especially during the "islamic golden age" (8th to 13th centuries),[1][2] as well as the late medieval period, especially in the emirate of granada and the ottoman empire.

science and technology in the islamic world adopted and preserved knowledge and technologies from contemporary and earlier civilizations, including persia, india, china, and greece-roman antiquity, while making a number of improvements and innovations.