Which two objects can be inserted in the same transaction? (Choose two.)

A company has a custom component that allows users to search for records of a certain object type by invoking an Apex Controller that returns a list of results based on the user's input, when the search Is completed, a searchComplete event is fired, with the results put in a results attribute of the event. The component is designed to be used within other components and may appear on a single page more than once.
What is the optimal code that should be added to fire the event when the search has completed?

Recently a Salesforce org's integration failed because it exceeded the number of allowed API calls in a 24-hour period. The integration handles a near real-time, complex insertion of data into Salesforce.
The flow of data is as follows:
* The integration looks up Contact records with a given email address and, if found, the integration adds a Task to the first matching Contact it finds.
* If a match is not found, the integration looks up Lead records with a given email address and, if found, the integration adds a Task to the first matching Lead it finds.
* If a match is not found, the integration will create a Lead and a Task for that newly created Lead.
What is one way in which the integration can stay near real-time, but not exceed the number of allowed API calls in a 24-hour period?

A developer needs to create a Lightning page for entering Order Information. An error message should be displayed if the zip code entered as part of the Order's shipping address is not numeric. What is a recommended way for the error message be displayed to the end user?

Employee_c is a Child object of Company_c. The Company_c object has an external Id field Company_ld_c.
How can a developer insert an Employee_c record linked to Company_c with a Company_ld_c of '999'?