In environmental science, experimental design is an extremely important part of the scientific method. When a scientist seeks to prove or disprove a hypothesis, he or she must carefully design the experiment so that it tests only one thing, or variable.
Borderline personality disorder (BPD), also known as emotionally unstable personality disorder, is a long term pattern of abnormal behavior characterized by unstable relationships with other people, unstable sense of self, and unstable emotions.
The main feature of borderline personality disorder (BPD) is a pervasive pattern of instability in interpersonal relationships, self-image and emotions. People with borderline personality disorder are also usually very impulsive, oftentimes demonstrating self-injurious behaviors (risky sexual behaviors, cutting, suicide attempts).