Explanation
On autonomous there's no patching needed. But on the regular DB Cloud services you need to patch the DB and the OS. During the creation on the OCDB the first DB is created automatically Oracle automatically takes care of Operating system Installation/Configuration, Grid Infrastructure, ASM diskgroup Creation/Configuration , and database softwareInstallation and first database on the DB System.
that's all when Creating DB Systems. and then the customer responsible to apply the patches to the database and OS

Explanation
Remote VCN peering is the process of connecting two VCNs in different regions (but the same tenancy ). The peering allows the VCNs' resources to communicate using private IP addresses without routing the traffic over the internet or through your on-premises network. Without peering, a given VCN would need an internet gateway and public IP addresses for the instances that need to communicate with another VCN in a different region.
At a high level, the Networking service components required for a remotepeering include:
- Two VCNs with non-overlapping CIDRs, in different regions that support remote peering. The VCNs must be in the same tenancy.
- A dynamic routing gateway (DRG) attached to each VCN in the peering relationship. Your VCN already has a DRG if you're using an IPSec VPN or an Oracle Cloud Infrastructure FastConnect private virtual circuit.
A remote peering connection (RPC) on each DRG in the peering relationship.
A connection between those two RPCs.
Supporting route rules to enable traffic to flow over the connection, and only to and from select subnets in the respective VCNs (if desired).
Supporting security rules to control the types of traffic allowed to and from the instances in the subnets that need to communicate with the other VCN.

Explanation
Pre-authenticated requests provide a way to let you access a bucket or an object without having your own credentials. For example, you can create a request that lets you upload backups to a bucket without owning API keys.
When you create a bucket, the bucket is considered a private bucket and the access to the bucket and bucket contents requires authentication and authorization. However, Object Storage supports anonymous, unauthenticated access to a bucket. You make a bucket public by enabling read access to the bucket.
pre-authenticated requests have to select expiration date

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 amajor 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
The Oracle Cloud Infrastructure Block Volume service provides you with the capability to group together multiple volumes ina volume group. A volume group can include both types of volumes, boot volumes, which are the system disks for your Compute instances, and block volumes for your data storage. You can use volume groups to create volume group backups and clones that are point-in-time and crash-consistent.
This simplifies the process to create time-consistent backups of running enterprise applications that span multiple storage volumes across multiple instances. You can then restore an entire group of volumes from a volume group backup.
To create a backup of the volume group
Open the navigation menu. Under Core Infrastructure, go to Block Storage and click Volumes Groups.
In the Volume Groups list, click Create Volume Group Backup in the Actions menu for the volume group you want to create a backup for.