Explanation
References:
A fault domain is a grouping of hardware and infrastructure within an availability domain. Each availability domain contains three fault domains. Fault domains provide anti-affinity: they let you distribute your instances so that the instances are not on the same physical hardware within a single availability domain.

Explanation
Autonomous Database automatically backs up your database for you.In addition to automatic backups Autonomous Database also allows you take manual backups to your Oracle Cloud Infrastructure Object Storage. for example if you want to take a backup before a major change to make restore and recovery faster.
Also, Manual backups are only supported with buckets created in the standard storage tier if you provision an Autonomous Data Warehouse instance named ADWC1, the bucket name should be backup_adwc1 (the bucket name is lowercase)

Explanation
References:
(1) => Populated by Default(0) => Not Populated by Default
Resources==========Subnets (0)Route Tables (1)Internet Gateways (0)Dynamic Routing Gateways (0)Network Security Groups (0)Security Lists (1)DHCP Options (1)Local Peering Gateways (0)NAT Gateways (0)Service Gateways (0)

A service gateway lets resources in your VCN privately access specific Oracle services, without exposing the data to an internet gateway or NAT. The resources in the VCN can be in a private subnet and use only private IP addresses. The traffic from the VCN to the service of interest travels over the Oracle network fabric and never traverses the internet.
To give your VCN access to a given service CIDR label, you must enable that service CIDR label for the VCN's service gateway. You can do that when you create the service gateway, or later after it's created. You can also disable a service CIDR label for the service gateway at any time.
For traffic to be routed from a subnet in your VCN to a service gateway, you must add a rule accordingly to the subnet's route table. The rule must use the service gateway as the target.
Reference:
https://blogs.oracle.com/cloud-infrastructure/connect-private-instances-with-oracle-servicesthrough-an-oracle-cloud-infrastructure-service-gateway