A person or thing that closely resembles another, as in Our grandson is a carbon copy of his dad. Originally this term meant a copy of a document made by using carbon paper. The linguistic transfer to other kinds of duplicate survived the demise of carbon paper (replaced by photocopiers, computer printers, and other more sophisticated devices). [ c. 1870 ]
The severity of symptoms depends on whether the injury is mild, moderate or severe. 1  Mild traumatic brain injury, also known as a concussion, either doesn't knock you out or knocks you out for 30 minutes or less. 2  Moderate traumatic brain injury causes unconsciousness lasting more than 30 minutes. Symptoms of moderate traumatic brain injury are similar to those of mild traumatic brain injury but more serious and longer-lasting. Severe traumatic brain injury knocks you out for more than 24 hours. Symptoms of severe traumatic brain injury are also similar to those of mild traumatic brain injury but more serious and longer-lasting.
If the animal is able to identify the original stimulus, it is rewarded with a treat. The animals didn't quite ace the test. In fact, average memory span across all species was a paltry 27 seconds. Bees' memories lasted about 2.5 seconds, chimps about 20 seconds. Dogs came out on top, but their memories dried up after only 70 seconds.