How do I verify if id, lastName, firstName, email, title, picture JSON object keys are being populated or not in JMeter

I want to write an API validation script for following REST API’s using dummyapi website where I want to verify if id, lastName, firstName, email, title, picture JSON object keys are being populated or not in JMeter.

I also want to get a value of id for a specific user. How would I be able to this? i