Explanation:
Which settings are swapped?
When you clone configuration from another deployment slot, the cloned configuration is editable. Some configuration elements follow the content across a swap (not slot specific), whereas other configuration elements stay in the same slot after a swap (slot specific). The following lists show the settings that change when you swap slots.
Box 1 : On
Settings that are swapped:
General settings, such as framework version, 32/64-bit, web sockets
App settings (can be configured to stick to a slot)
Connection strings (can be configured to stick to a slot)
Handler mappings
Public certificates
WebJobs content
Hybrid connections *
Virtual network integration *
Service endpoints *
Azure Content Delivery Network *
Features marked with an asterisk (*) are planned to be unswapped.
So web sockets settings will be swapped. So Production will have web sockets settings from "Off" to "On" after the swap slot.
Box 2: App1-prod.contoso.com
Settings that aren't swapped:
Publishing endpoints
Custom domain names
Non-public certificates and TLS/SSL settings
Scale settings
WebJobs schedulers
IP restrictions
Always On
Diagnostic settings
Cross-origin resource sharing (CORS)
So Custom domain names will not be swapped. So Production will have Custom domain names of its own after the swap slot.
Reference:
https://docs.microsoft.com/en-us/azure/app-service/deploy-staging-slots#what-happens-during-a-swap

Explanation
URL Path Based Routing allows you to route traffic to back-end server pools based on URL Paths of the request.
In the question there are two different path from where the traffic is getting generated as below
https://adatum.com/internal
https://adatum.com/external
So in this case we can use URL path-based routing feature of Application Gateway.

Reference:
https://docs.microsoft.com/en-us/azure/application-gateway/url-route-overview

Explanation
To assign a license, under Azure Active Directory > Licenses > All Products, select one or more products, and then select Assign on the command bar.
References: https://docs.microsoft.com/en-us/azure/active-directory/fundamentals/license-users-groups

Explanation:
Box 1: never
For Subnet 10.2.9.0/24, endpoint (Refer to first endpoint) is not enabled into the storage account shown in the exhibit. Hence there would not be any connectivity to the file shares in storage account. To establish this connection you must have to enable the endpoint.
Box 2: never
After you configure firewall and virtual network settings for your storage account, select Allow trusted Microsoft services to access this storage account as an exception to enable Azure Backup service to access the network restricted storage account. As this required setting is missing , so Azure backup will not be able to take backup of unmanaged disks.

Reference:
https://docs.microsoft.com/en-us/azure/storage/common/storage-private-endpoints
https://azure.microsoft.com/en-us/blog/azure-backup-now-supports-storage-accounts-secured-with-azurestorage-firewalls-and-virtual-networks/

Which settings are swapped?
When you clone configuration from another deployment slot, the cloned configuration is editable. Some configuration elements follow the content across a swap (not slot specific), whereas other configuration elements stay in the same slot after a swap (slot specific). The following lists show the settings that change when you swap slots.
Box 1 : On
Settings that are swapped:
General settings, such as framework version, 32/64-bit, web sockets
App settings (can be configured to stick to a slot)
Connection strings (can be configured to stick to a slot)
Handler mappings
Public certificates
WebJobs content
Hybrid connections *
Virtual network integration *
Service endpoints *
Azure Content Delivery Network *
Features marked with an asterisk (*) are planned to be unswapped.
So web sockets settings will be swapped. So Production will have web sockets settings from "Off" to "On" after the swap slot.
Box 2: App1-prod.contoso.com
Settings that aren't swapped:
Publishing endpoints
Custom domain names
Non-public certificates and TLS/SSL settings
Scale settings
WebJobs schedulers
IP restrictions
Always On
Diagnostic settings
Cross-origin resource sharing (CORS)
So Custom domain names will not be swapped. So Production will have Custom domain names of its own after the swap slot.
Reference:
https://docs.microsoft.com/en-us/azure/app-service/deploy-staging-slots#what-happens-during-a-swap