What is a capability of schema builder? (Select 2)

At Universal Containers, each admin and developer use a separate developer pro sandbox. Configuration and code are then migrated to a partial data sandbox for combination and initial testing. Once approved the configuration and code are then migrated to a full sandbox for final toad and regression testing before going to production.
When should the full sandbox be refreshed?

Universal Containers has a junction object called Invoices with a primary Master-Detail relationship with Accounts and a secondary Master-Detail relationship with Contacts. The app builder has a requirement to change the primary Master-Detail relationship to Lookup.
What happens to the Master-Detail relationship with Contacts?

Universal containers would like to use a chatter group for their mergers and acquisition team to collaborate on potential new projects. This group should not be visible for non-members to see or join, and can be accessed by invite only. Which chatter Group type should the App Builder recommend?

UC has a requirement that an opportunity should have a field showing the value of its associated account's billing state. This value should not change after the opportunity has been created. Is there a recommended solution to configure this automated behavior?