Explanation
https://docs.cloud.oracle.com/iaas/Content/Object/Tasks/usingpreauthenticatedrequests.htm You can create an unlimited number of pre-authenticated requests.
You can't edit a pre-authenticated request. If you want to change user access options in response to changing requirements, you must create a new preauthenticated request.
URL: https://docs.cloud.oracle.com/iaas/Content/Object/Tasks/managingbuckets.htm You can change a bucket's access from public to private or from private to public. Changing the type of access doesn't affect existing pre-authenticated requests. Existing pre-authenticated requestsstill work.

Explanation
References:https://cloud.oracle.com/database/faq#backup
Can I set up Data Guard across Availability Domains?Yes, you can set up Data Guard in the same or different Availability Domains in a region. However, Oracle recommends that you set up your Data Guard configuration across Availability Domains.Can I set up Data Guard across Oracle Cloud Infrastructure regions?Yes, you can set up Data Guard across regions,
"but the Database Cloud Service Data Guard feature currently does not support it. " You can manually set up Data Guard across regions by logging on to your host and using DGMGRL. You must enable an internet gateway on the primary and standby DB system VCN for Data Guard to transport logs across regions. Learn more about DGMGRL.
To configure a Data Guard system across regions or between on-premises and Oracle Cloud Infrastructure DB systems, you must access the database host directly and use the DGMGRL utility.
https://docs.cloud.oracle.com/iaas/Content/Database/Tasks/usingdataguard.htm

Explanation
STRONG CONSISTENCYWhen a read request is made, Object Storage always serves the most recent copy of the data that was written to the system.DURABILITYObject Storage is aregional service. Data is stored redundantly across multiple storage servers. Object Storage actively monitors data integrity using checksums and automatically detects and repairs corrupt data. Object Storage actively monitors and ensures data redundancy.If a redundancy loss is detected, Object Storage automatically creates more data copies. For more details about Object Storage durability, see the Oracle Cloud Infrastructure Object Storage FAQ.CUSTOM METADATAYou can define your own extensive metadata as key-value pairs for any purpose. For example, you can create descriptive tags for objects, retrieve those tags, and sort through the data. You can assign custom metadata to objects and buckets using the Oracle Cloud Infrastructure CLI or SDK. See Software Development Kits and Command Line Interface for details.ENCRYPTIONObject Storage employs 256-bit Advanced Encryption Standard (AES-256) to encrypt object data on the server. Each object is encrypted with its own key. Data encryption keys are encryptedwith a master encryption key that is frequently rotated.
Encryption is enabled by default and cannot be turned off.

Explanation
An internet gateway as an optional virtual router that connects the edge of the VCN with the internet. To use the gateway, the hosts on both ends of the connection must have public IP addresses for routing. Connections that originate in your VCN and are destined for a public IP address (either inside or outside the VCN) go through the internet gateway. Connections that originate outside the VCN and are destined for a public IP address inside the VCN go through the internet gateway.
Working with Internet Gateways
You create an internet gateway in the context of a specific VCN. In other words, the internet gateway is automatically attached to a VCN. However, you can disable and re-enable the internet gateway at any time.
Compare this with a dynamic routing gateway (DRG), which you create asa standalone object that you then attach to a particular VCN. DRGs use a different model because they're intended to be modular building blocks for privately connecting VCNs to your on-premises network.
For traffic to flow between a subnet and an internetgateway, you must create a route rule accordingly in the subnet's route table (for example, destination CIDR = 0.0.0.0/0 and target = internet gateway). If the internet gateway is disabled, that means no traffic will flow to or from the internet even if there's a route rule that enables that traffic. For more information, see Route Tables.
For the purposes of access control, you must specify thecompartment where you want the internet gateway to reside. If you're not sure which compartment to use, put the internet gateway in the same compartment as the cloud network. For more information, see Access Control.
You may optionally assign a friendly name to the internet gateway. It doesn't have to be unique, and you can change it later. Oracle automatically assigns the internet gateway a unique identifier called an Oracle Cloud ID (OCID). For more information, see Resource Identifiers.
To delete an internet gateway, it does not have to be disabled, but theremust not be a route table that lists it as a target.
AS per compute instances can connect to the Internet so you use egress no ingress

Explanation
If a bare metal DB system requires more compute node processing power, you can scale up (increase) the number of enabled CPU cores in the system without impacting the availability of that system but you can't increase the storage If the original DB system VM shapeuses a single node, running databases on the DB system nodes are sequentially stopped and then restarted on the new shape so not dynamic