Chapter 9: Computing with App Engine

1. B. Versions support migration. An app can have multiple versions, and by deploying with the --migrate parameter, you can migrate traffic to the new version, so option B is the correct answer. Services are a higher-level abstraction and represent the functionality of a microservice. An app may have multiple services, but they serve different purposes. Instances execute code in a version. Instances may be added and removed as needed, but they will run only one version of a service. Instance groups are part of Compute Engine and are not an App Engine component.
2. A. Autoscaling enables setting a maximum and minimum number of instances, which makes option A correct. Basic scaling does not support maximum and minimum instances. Option C is not recommended because it is difficult to predict when load will peak and even if the schedule is predictable today, it may change over time. Option D is wrong; there is no instance detection option.
3. B. Application is...