A resource group is a logical container for Azure resources. When you create a resource group, you specify which location to create the resource group in. However, when you create a virtual machine and place it in the resource group, the virtual machine can still be in a different location (different datacenter). Therefore, creating multiple resource groups, even if they are in separate datacenters does not ensure that the services running on the virtual machines are available if a single data center fails.
https://docs.microsoft.com/en-us/azure/azure-resource-manager/management/overview#resource-groups

Explanation:
Box 1: Yes
You can use the same account to manage multiple subscriptions. You can create an additional subscription for your account in the Azure portal. You may want an additional subscription to avoid hitting subscription limits, to create separate environments for security, or to isolate data for compliance reasons.
Box 2: No
You cannot merge two subscriptions into a single subscription. However, you can move some Azure resources from one subscription to another. You can also transfer ownership of a subscription and change the billing type for a subscription.
Box 3: Yes
A company can have multiple subscriptions and store resources in the different subscriptions. However, a resource instance can exist in only one subscription.
References:
https://docs.microsoft.com/en-us/azure/cost-management-billing/manage/create-subscription

Section: Describe Cloud Concepts
Explanation:
Azure Site Recovery helps ensure business continuity by keeping business apps and workloads running during outages. Site Recovery replicates workloads running on physical and virtual machines (VMs) from a primary site to a secondary location.
Reference:
https://docs.microsoft.com/en-us/azure/site-recovery/site-recovery-overview

Explanation
Azure Cosmos DB is an example of a platform as a service (PaaS) cloud database provider.
References:
https://docs.microsoft.com/en-us/azure/cosmos-db/database-security