During the dark ages (roughly from the 5th to the 10th century a. turmoil in europe largely halted the progress of western science. which culture provided the vital link between the astronomy of ancient greece and that of medieval europe during this time?

The Islamic World

The Islamic Golden Age is a period in the history of Islam from the 8th to the 14th century, roughly matching the Medieval Period in Europe. During this period, much of the Islamic world was ruled as caliphates, and the rulers were interested in acquiring knowledge from their conquered territories. Many classical works that would otherwise have been lost were translated from Persian, Greek, Egyptian, Chinese, Indian and Phoenician into Arabic, and therefore preserved. This was done in madrasas and institutions such as the House of Wisdom in Baghdad.

Islamic scholars also excelled in philosophy, science and theology, and they translated the work of ancient Greek philosophers, including Plato, Aristotle, Hippocrates, Ptolemy and Archimedes. Astronomy was greatly developed during this period thanks to the work of Abd al-Rahman al-Sufi (first referenced the Andromeda Galaxy, the closest galaxy to ours), Nasir al-Din al-Tusi (creator of trigonometry as a discipline) and  Ibn al-Shatir (reformed the Ptolemaic models of the Sun, Moon and planets).

the great wall of china worked as a defense for the feudal states of the zhou dynasty to the north. during the warring states period more walls were put up to defend the borders of the different kingdoms. it was semi successful because despite the wall, the mongols eventually conquered china also the great wall provided protection to the economic development and cultural progress, safeguarded the trading routes such as the silk road, and secured transmission of information and transportation. @jayxboof

length of the cultivating season was not a problem of new england agriculture