A fictional support portal, ticket inventory service and media catalog need different request paths. You will assemble a read service, estimate its behavior after a replica fails and make storage choices from the work each team does. Treat the workload as part of the question rather than a decoration around the diagram.
Use the same parts palette for each design, but add only the parts that have a purpose. A cache can reduce source reads while creating freshness work. A load balancer can route around an unhealthy process while leaving a database as a single failure point. The questions mix those limits with index selection and concurrent writes. Choose a reason as well as an option whenever the worksheet asks for a decision.