Explanation
An after save flow is a type of flow that runs in the background after a record is saved and performs actions based on the record data or changes. An after save flow does not require user input or interaction and can be triggered by a record-triggered flow element or by an Apex trigger. In this case, you can create an after save flow that runs when a case record is updated and delivers status update email to customers based on certain criteria or conditions. References:
https://help.salesforce.com/s/articleView?id=sf.flow_trigger_types.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.flow_concepts_trigger.htm&type=5

Explanation
The change can be made through the desktop site by using the Edit All button on the related list of products on the opportunity page. This button allows you to edit multiple products at once and change their price book entries. You cannot use this button on the mobile app, as it is not supported. You also cannot change the price book on the opportunity once it has products added to it, unless you remove all the products first. References:
https://help.salesforce.com/s/articleView?id=sf.opportunity_products_edit.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.opportunity_products_change_pricebook.htm&type=5

Explanation
A roll-up summary field is a type of field that calculates values from related records and displays them on the parent record. A roll-up summary field can be used to count, sum, min, or max values from child records. You can create a roll-up summary field on an object that has a master-detail relationship with another object. In this case, you can create a roll-up summary field on Room that counts the number of Equipment records related to it. References:
https://help.salesforce.com/s/articleView?id=sf.fields_about_roll_up_summary_fields.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.fields_defining_field_types.htm&type=5

Explanation
The Delete permission is missing on the user for Accounts is what is preventing the user from completing the merge. Merging accounts is a way to combine up to three duplicate accounts into one master record and update the related records accordingly. Merging accounts requires the Delete permission on accounts because merging accounts involves deleting the duplicate records and keeping only the master record.

Explanation
As explained in question 3, a price book is a list of products and their prices for a specific segment of customers or market. By creating a new price book for the U.K product pricing, Northern Trail Outfitters (NTO) can offer different prices for their products in the U.K market due to shipping and raw material cost differences. The price book can also specify which currency is used for the prices, such as pounds or euros.
References: https://help.salesforce.com/s/articleView?id=sf.products_pricebooks_def.htm&type=5