Select the correct text in the passage. Which of these advances caused the fireplace to become the central feature of kitchens? Evolution of Culinary Techniques Cooking on an open fire was the earliest culinary technique. Boiling, which evolved as the next technique for cooking food, led to the design of customized utensils. People in early settlements, such as the Egyptians, used small vessels (cauldrons). They hung these vessels over a fire to absorb and concentrate heat for cooking. The Egyptians also invented sealable storage silos to preserve surplus grains for many years. Native Americans used clay vessels for cooking and storing foods. They used these vessels long before European settlers arrived with pots and kettles. Stone cooking pots, used for cooking maize, evolved about 7000 BC in Central America. The pots were so heavy that they were often left permanently in the center of the cooking space.