Final answer:
The easiest way to tell whether a teenager is lying about his/her age is by asking for official identification documents such as a driver's license or a birth certificate.
Step-by-step explanation:
The easiest way to tell whether a teenager is lying about his/her age is by asking for official identification documents such as a driver's license or a birth certificate. These documents provide concrete proof of the teenager's age and are generally accepted as valid evidence.
For example, if a teenager claims to be 16 years old but does not possess a driver's license or any other form of identification, it raises suspicions about the accuracy of their claim.
By requesting official documents, you can verify the teenager's age and determine whether they are being truthful or not.