Final answer:
Oliguria is a condition with a reduced urine output, usually below 600 ml/day. In a 70kg patient over a 12-hour period, the urine output should be at least 300 ml. Anuria is the absence of urine or an excretion of less than 10 ml/day, commonly caused by acute renal failure and nephritis.
Step-by-step explanation:
Oliguria is a condition characterized by the excretion of urine less than 600 ml/day. It can be caused by fever, shock, vomiting, or diarrhea. The urine output in a 70kg patient over a 12-hour period should be at least 25 ml/hour or a total of 300 ml. Anuria, on the other hand, refers to the absence of urine or an excretion of less than 10 ml/day. It is commonly observed in acute renal failure and nephritis.