Final answer:
Concrete footings and foundation walls, in the context of the quantity survey method of costing improvements, refer to General construction, as they are key structural components of a building.
Step-by-step explanation:
Under the quantity survey method of costing improvements, concrete footings and foundation walls refer to General construction. These are parts of the structural aspects of a building, where concrete footings are crucial in distributing the load of the structure to the ground and preventing settling, while foundation walls support the above structure and hold back the surrounding earth. This method involves listing every material and labor required for a construction project and calculating their costs to come up with an accurate budget.