What is a system called when neither energy nor matter is exchanged between the system and the surroundings?

A) Closed system
B) Free energy
C) Isolated system
D) Open system

Let the ed50 of a recreational drug be defined as the amount required for 50% of a test group to feel high or get a buzz. if the ed50 value of ethanol is 470 mg/kg body mass, what dose would a 70 kg party goer need to quickly consume in order to have a 50% chance of getting a buzz? 235 mg 470 mg 32,900 mg 35,000,000 mg