Final answer:
Suppliers that provide raw materials or components for manufacturing are known as first-tier suppliers, which are crucial to the secondary economic sector activities.
Step-by-step explanation:
Suppliers that provide raw materials, basic services, or manufacturing components for the primary firm's manufacturing or service production processes are known as first-tier suppliers. These suppliers are essential to the manufacturing process as they provide the inputs needed for the production of finished goods. In the economic structure of sectors, the secondary economic sector activities involve processing these raw materials through manufacturing, thereby transforming natural resources into finished products. This sector is vital as it helps in the creation of goods which is a significant step up from the primary sector that merely extracts and produces raw materials.