B. Blood pressure refers to the lateral pressure of blood on the blood vessel wall when blood flows in the blood vessel, usually referring to the arterial blood pressure of systemic circulation. The measurement of blood pressure is generally measured at the brachial artery of the upper arm with a sphygmomanometer, so it is wrong.
C, arterial blood pressure is too high, it is not easy to stop bleeding after blood drawing, while venous blood vessels are generally located in superficial parts, with low pressure and easy to stop bleeding, so doctors will puncture venous blood vessels on the body surface when blood drawing. Therefore, it is wrong.
D. Sweating is a physiological function of human excretion and body temperature regulation. When sweating a lot, the reabsorption of water by renal tubules increases to reduce urine output, so it is wrong.
So choose: a