Models are the representative of the real world. A model system can provide information of the reactions going on inside a living system. A model should provide the following advantages which are: it should be easy to culture in lab., it should have a short life cycle, it should be inexpensive to operate, it should be easily genetically manipulated, it should be a representative of the original population, I should provide accurate result which might happen in the original population and it should provide economically important results etc. Model can include an organism or it can be a Computer based simulation.
Answer: it is used primarily in conjunction with surgical anesthesia
Explanation: it is one of the synthetic opioid , it is used intravenously as anesthesia and to treat pain. It is given with a muscle relaxant and a sedative hypnotic. The effect is quick in the body and central nervous system and can last less than 2 hours.
See that river on the bottom? That water has been flowing in the canyon for a long time and has slowly been chipping away at the rocks to give what you see today.