What is the name for an object that enables a many-to-many relationship between two other objects?

Universal Containers uses a private sharing model for opportunities. This model CANNOT be changed due to a regional structure A new sales operations team has been created. This team needs to perform analysis on Opportunity data, all should have read arid write access to all Opportunities.
What are two recommended solutions for the app builder to give the users appropriate access? Choose 2 answers

What happens when you convert a picklist to a multi-select picklist? (Choose two.)

At UVC, multiple departments utilize the Case object for different purposes. Some users submit cases while other users provide customer support with case records. What is the minimum required configuration for an App Builder to enable different users to see different fields, based on the case type?

Representatives at Cloud Kicks use Salesforce to record information for new Leads. When new prospects are added, an outbound message is sent to the data warehouse with the Lead's information.
What automation tool should an app builder use to meet this requirement?