Final answer:
The primary enabler of the internal integration of key supply chain processes is a firm's ERP system.
Step-by-step explanation:
The primary enabler of the internal integration of key supply chain processes is a firm's ERP system. ERP stands for Enterprise Resource Planning, and it is a software solution that integrates and manages various business functions such as inventory management, production planning, customer relationship management (CRM), and finance. By implementing an ERP system, firms can streamline their supply chain processes, improve communication and collaboration with suppliers and customers, optimize inventory levels, and enhance overall operational efficiency.