Before revision: Core business functions are always directly involved in the primary cash flows of the revenue model or models of the business, whereas non-core business functions usually are not, meaning that the business can technically operate without non-core business functions without impacting the primary cash flows, whereas the core business functions are essential to the continuance of its primary cash flows.
After revision: Core business functions are always immediately involved in the primary cash flows of the revenue model or models of the business, whereas non-core business functions typically are not, which means that the business can hypothetically operate without non-core business functions without impacting primary cash flows, whereas the core business functions are essential to the continuance of its primary cash flows.