Explanation
Changing the default value of the Lead Source field from 'Web' to 'Trade Show' is the best way to help the sales reps when they create these lead records, as it will automatically populate the field with the correct value, and save them time and effort.

Explanation
The contact relationship on case is used to indicate the individual who has called in to the support center. The contact field on case is a lookup field that allows the user to select a contact from the related account or any other account. The owner relationship on case is used to indicate the user who is responsible for working on the case. The account relationship on case is used to indicate the company or organization that the case is related to.

Explanation
Using the Accounts with Opportunities report type is the best way to create a report of all Accounts with Opportunities. A report type defines the set of records and fields available to a report based on the relationships between a primary object and its related objects. The Accounts with Opportunities report type includes accounts that have at least one related opportunity, and allows fields from both objects to be displayed in the report. Using the Accounts report type would not work, because it would include accounts that do not have any related opportunities. Using the Opportunities report type would not work, because it would not include account fields in the report.