define a supply chain as a network of manufacturers and service providers that work together to create products or services needed by end users. What are some o​‌‍‍‍‌‍‍‌‌‌‍‌‍‍‌‌‍‌‍‍​f the different supply chains that support products such as the iPhone? How does Apple manage the supply chain that allows users to download various software apps to their iPhones​‌‍‍‍‌‍‍‌‌‌‍‌‍‍‌‌‍‌‍‍​?