Final answer:
Azure Policy is the service in Azure used to define, assign, and manage standards for resources in your environment.
Step-by-step explanation:
The service in Azure that you use to define, assign, and manage standards for resources in your environment is Azure Policy. Azure Policy is a service in Microsoft Azure that allows you to create and enforce policies to ensure compliance and governance in your Azure environment. These policies define rules that resources must follow and can be used to prevent non-compliant resources from being created or to remediate existing non-compliant resources.