Not until the advent of biochemistry could the anatomist see through the microscope which cells carry specific enzymes or gauge how active these enzymes are in different cells under various conditions.
【正确答案】 C
【答案解析】解析：gauge“测量，评估”。discern“辨认，识别”；grasp“抓住，领会”；measure“测量”；estimate“评估(尤指通过计算来估测)”。由句意可知，此处应表示“(通过观察来)测量”之意，故选C。