Explanation
Before Save Flows are a type of record-triggered flow that run before a record is saved and can update fields on that record without any additional actions or DML operations. They are faster and more efficient than workflow rules or process builder for simple field updates when a record is created or updated. References:
https://help.salesforce.com/s/articleView?id=sf.flow_concepts_before_save_update.htm&type=5

Explanation
To see certain information about one or more cases when referencing the contact record, an administrator can use two methods: edit the Related List component in the Lightning App Builder and choose Related List as the related list type; and use the page layout editor to include the appropriate column in the Cases related list. The Related List component is a component that allows users to view and edit records related to a parent record on a record page. The Related List component has two types: Related List and Enhanced List. The Related List type shows records in a table format with columns that match the page layout of the parent record. The Enhanced List type shows records in a compact format with fewer columns and actions. To change the type of the Related List component, an administrator can use the Lightning App Builder and select either Related List or Enhanced List from the properties panel. The page layout editor is a tool that allows administrators to control how fields, related lists, buttons, etc., are arranged on a record detail or edit page for each object. To include appropriate columns in a related list, such as case name, case ID, customer name, case reason, case status, and case creation date for cases related to contacts, an administrator can use the page layout editor and drag and drop the desired fields from the palette to the Cases related list on the contact page layout.
References: https://help.salesforce.com/s/articleView?id=sf.lex_related_lists_component.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.customize_pagelayouts_overview.htm&type=5

Explanation
Lightning app pages, Chatter, and dashboards are three items that are available in the mobile navigation menu.
The mobile navigation menu allows users to access different items in the Salesforce mobile app, such as objects, apps, or utilities. Users can customize their mobile navigation menu by adding or removing items and changing their order. References: https://help.salesforce.com/s/articleView?id=sf.app_nav_setup.htm&type=5