Which of the following roles can update cart layout?

Universal Containers uses a custom object to track customer complaints. The company wants to have a field on the custom object where they can include a reference to another complaint.
Which type of relationship can be used to accomplish this?

Recently a Salesforce org's integration failed because it exceeded the number of allowed API calls in a 24-hour period. The integration handles a near real-time, complex insertion of data into Salesforce.
The flow of data is as follows:
* The integration looks up Contact records with a given email address and, if found, the integration adds a Task to the first matching Contact it finds.
* If a match is not found, the integration looks up Lead records with a given email address and, if found, the integration adds a Task to the first matching Lead it finds.
* If a match is not found, the integration will create a Lead and a Task for that newly created Lead.
What is one way in which the integration can stay near real-time, but not exceed the number of allowed API calls in a 24-hour period?

Which table stores CI Relationship data?

How to add restriction on moving incidents from one state to another?