Which command is used to apply changes and create resources defined in your configuration?

The command used to apply changes and create resources defined in your configuration is "terraform apply." This command executes the actions necessary to reach the desired state defined in your Terraform configuration file. When you run it, Terraform will read the configuration files, determine the changes needed to make the actual infrastructure match the desired state, and then prompt you for approval before making any changes.

This command is critical because it not only provisions new resources but also makes updates to existing resources or removes resources as dictated by the changes in your configuration. This could include creating virtual machines, setting up network components, or modifying storage configurations, depending on what is defined in the Terraform scripts.

The other options, such as "terraform plan," are used for different purposes, primarily to create an execution plan without making any changes. "Terraform start" and "terraform deploy" are not valid Terraform commands, as they do not exist in the Terraform CLI structure.