Question

______________ is characterized by one or more of three key symptoms, including extreme inattention, hyperactivity, and impulsivity.

Answer 1

I believe the answer is: Attention deficit/hyperactivity disorder

Attention deficit/hyperactivity disorder happened when our brain constantly experiencing irregular pattern of impulses.
People with Attention deficit/hyperactivity disorder would have a really hard time in focusing all their time and attention in doing one specific activity such as sitting down to study for exam, doing homework, writing a long report, etc.