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.
Borderline personality disorder: pervasive pattern of abrupt mood swings, instability in relationships, self-image, identity, behavior and affect, often leading to self-harm and impulsivity. Histrionic personality disorder: pervasive pattern of attention-seeking behavior and excessive emotions.