This is actually a trick question as contrary to common beliefs they do not exist at the same level in the IT framework. There is a common fallacy that enterprise architecture interferes with the fluidity of the continuous delivery/continuous improvement model. In a high performing IT environment, architects and delivery teams have defined the delineation between planning and delivery in such a way that the architect teams provide a strategic roadmap for products. As delivery teams receive requirements, those can be matched against the roadmap to ensure that designs are aligned with the overall strategic direction of the IT organization.
When properly implemented, an environment which incorporates an Agile methodology with a functional enterprise architecture can increase effectiveness as the architectural framework can reduce the amount of design that needs to be done within the sprint cycle. Concurrently, by following an architectural framework development teams will have a library of reusable assets to draw upon as they start their development cycle. On the IT service management side of this equation, operational and support teams also benefit as and increase in the amount of reused assets simplifies the training and knowledge needed to support the product portfolios.
Without an enterprise architecture, product teams are often left to their own resources. As the organization grows, this often leads to disjointed IT solutions across product teams… which in turn increases the complexity for operation and confusion for the customers and executives when attempting to describe the portfolios that are provided.