Which defense emerged within medieval fortifications due to the undermining risk of surrounding stone walls?

💡 Explanation

The glacis, a sloping bank toward the wall's base, emerged because soil provides a poor medium for tunneling. Glacis construction prevented straightforward mine construction due to slope stabilization, therefore impeding easy access rather than allowing excavation.

• Which risk increased due to thermal expansion when crafting large Byzantine mosaics on exterior surfaces?
• Which mechanism causes rapid gas expansion within the priming chamber of early Chinese hand cannons?
• Which outcome arises when lead contamination affects the crafting process of an astrolabe's sighting vanes?
• Which structural problem developed historically in timber ship construction due to alternating wet and dry conditions?
• Which consequence resulted from differential cooling rates during ancient bronze casting?
• Which mechanism maintains soil stability on Inca agricultural terraces during heavy rainfall events?