When the bile can not be properly propelled from the not-mechanically-obstructed gallbladder or can not flow out of the end of the common bile duct properly, there is a state of biliary dyskinesia. So, biliary dyskinesia is a dynamically (functional...not fixed mechanical) obstructive, pain-producing disorder.
Two sections each with 20 questions, 35 minutes for each section. Each quantitative reasoning section (also common called the Math GRE sections) contains a mix of multiple choice, quantitative analysis, and user input questions.
The GRE score is a function of number of correct answers in all four sections i.e. Verbal - 1, Quant - 1, Verbal -2, Quant - 2. There is no negative marking and leaving a question doesn't impact the score at all. So go for all questions. Below are some facts about the GRE scoring.