These six types of events are categorized in to 3 levels of risks - High, Medium & Low:

Reference:
http://www.rebeladmin.com/2018/09/step-step-guide-configure-risk-based-azure-conditional-access-policies/

In the Reviewers section, select either one or more people to review all the users in scope. Or you can select to have the members review their own access. If the resource is a group, you can ask the group owners to review.

Reference:
https://docs.microsoft.com/en-us/azure/active-directory/governance/create-access-review
https://docs.microsoft.com/en-us/azure/active-directory/governance/manage-programs-controls

To email an alert to a user named [email protected] if the average CPU usage of a virtual machine named VM1 is greater than 70 percent for a period of 15 minutes, you can follow these steps:
In the Azure portal, search for and select the virtual machine named VM1.
In the left pane, select Alerts.
Select New alert rule.
In the New alert rule pane, enter the following information:
Name: Enter a name for the alert rule.
Description: Enter a description for the alert rule.
Condition: Select Metric measurement.
Resource: Select the virtual machine named VM1.
Metric: Select Percentage CPU.
Operator: Select Greater than.
Threshold: Enter 70.
Aggregation type: Select Average.
Period: Select 15 minutes.
In the Actions pane, select Add action group.
In the Add action group pane, enter the following information:
Name: Enter a name for the action group.
Short name: Enter a short name for the action group.
Email recipient: Enter the email address of the user you want to receive the alert. For example, [email protected].
Select OK.

Reference:
https://docs.microsoft.com/en-us/azure/active-directory/develop/active-directory-how-applications-are-added

The Standard tier extends the capabilities of the Free tier to workloads running in private and other public clouds, providing unified security management and threat protection across your hybrid cloud workloads. The Standard tier also adds advanced threat detection capabilities, which uses built-in behavioral analytics and machine learning to identify attacks and zero-day exploits, access and application controls to reduce exposure to network attacks and malware, and more.
Scenario: Security Operations Requirements
Litware must be able to customize the operating system security configurations in Azure Security Center.
Reference:
https://docs.microsoft.com/en-us/azure/security-center/security-center-pricing