Answer:
The technological development that helped the Mongols conquer lands was the bow, arrow, and horse saddle.
Step-by-step explanation:
The Mongols were a nomadic people who lived on the steppes of Central Asia and relied on horses for transportation and warfare. They were skilled horsemen and developed highly effective military tactics that made use of their mounted archery skills.
The Mongols' use of the bow and arrow was a key factor in their military success. They were able to produce highly efficient composite bows made of wood, horn, and sinew, which were powerful and accurate at long distances. The Mongols also developed a specialized horse saddle that allowed them to shoot arrows while mounted, allowing them to attack their enemies with great speed and mobility.
The combination of these technological developments allowed the Mongols to conquer a vast territory stretching from China to Europe, making them one of the most successful military powers in history. Their military successes were due in large part to their use of the bow, arrow, and horse saddle, which gave them a significant advantage over their enemies.