The sandbox copy engine creates an organization as part of each creation and refresh request. So, the organization ID of your sandbox changes each time your sandbox is refreshed.

In terms of the order of execution, what must be taken into account when using Validation rules & Workflows?

As an account's expiration approaches, send recurring e-mail notifications to the owner (2 weeks before, 1 week before, 3 days before, and 1 day before).
Which tool would you use for the following use case?

Which two will prevent a formula field from being referenced by a Roll-Up Summary field? (Choose two.)

A user's profile does not have any permissions to view a custom object.
However, the Organization Wide Defaults for the custom object are set to Public Read/Write. Users with this profile will still be able to access the custom object.