单项选择题 （单选）以下关于滤液流率的说法，正确的是（）*

单项选择题 【单选题】A careful analysis of cellular components discovers short-lived RNA species in which an adenine nucleotide is found with three phosphodiester bonds (linked to the 2’, 3’, and 5’ carbons). This transient structure is formed during which of the following processes? A、mRNA cap formation B、C、 D、 E、SplB、mRNA polyadenylationC、Transcription of rRNAD、Transcription of microRNAsE、Splicing of hnRNA

单项选择题 患者近2年来倦怠乏力，食欲减退，间歇性鼻出血，齿龈出血。今进食粗糙硬质食物后，突然大量呕鲜红色血，并出现黑便。检查：血压明显下降，心率l20次／分，腹部膨隆，有移动陛浊音，肝脾触诊不满意。应首选的止血措施是（）。