Explanation
Contract is a standard object that represents a contractual agreement between your company and a customer.
Case is a standard object that represents a customer's question or problem that needs to be resolved by your support team. Account is a standard object that represents an individual or an organization involved in your business, such as customers, competitors, partners, etc. These three objects are commonly used for service use cases in Salesforce. References: https://help.salesforce.com/s/articleView?id=sf.contract_fields.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.case_fields.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.account_fields.htm&type=5

Explanation
Validation rule is a tool that can be used to enforce data quality and business logic by preventing users from saving records that do not meet certain criteria. In this case, a validation rule can be created on the Opportunity object to display an error message if the Stage field is Closed lost and the Loss Reason field is blank.
References: https://help.salesforce.com/s/articleView?id=sf.fields_about_validation_rules.htm&type=5

Explanation
Mass delete records and data loader are two tools that can be used by Ursa Major Solar administrator undo import records into object mistake. Mass delete records tool allows administrators delete large numbers records meet certain criteria once setup interface; it can used undo import records into object mistake selecting records imported mistake deleting them mass delete records tool setup interface Data loader tool allows administrators import export delete large numbers records using CSV files command line interface API calls; it can used undo import records into object mistake using CSV file contains IDs records imported mistake deleting them data loader tool command line interface API calls Weekly data export data import wizard are not tools undo import records into object mistake because they either export import records but not delete them.
References: https://help.salesforce.com/s/articleView?id=sf.admin_massdelete.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.data_loader.htm&type=5

Explanation
A flow can be active or inactive depending on whether you want it to run or not. An inactive flow cannot be run by users or processes until you activate it. If a flow in production is supposed to create new records but it is not doing so, it could be because the flow is inactive and needs to be activated. References:
https://help.salesforce.com/s/articleView?id=sf.flow_distribute_activate.htm&type=5

Explanation
To use as an identifier when importing and updating records from a separate system, an administrator should use External ID field type on an object. External ID fields allow storing unique identifiers from external systems and using them for matching records during import or update operations. External ID fields can also be used for upsert operations that insert new records or update existing ones based on external ID values. For example, an administrator can create an External ID field on Account object that stores account numbers from an external ERP system and use it for importing or updating accounts from that system. Rich Text field, Record ID, and Auto-Number field are not suitable for using as identifiers when importing and updating records from a separate system. References:
https://help.salesforce.com/s/articleView?id=sf.fields_about_field_types.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.data_loader_upsert.htm&type=5