Which type of field do administrators use when creating a junction object?

Which report should a System Administrator use to display the number of Contacts related to an Account?

Universal container is using a private sharing model. The US sales director needs full access to all records of the US sales representatives. How can this be accomplished?

Universal Containers needs to upload 1 million new Account records to Salesforce.
What should the Administrator recommend to perform this data upload?

Universal Containers wants to create a new sales team that focuses exclusively on small to medium business customers. This group will track information with the same fields and picklist values but will have 2 new options on Stage field. How should the system administrator accomplish this task?