Solved by a verified expert:The comparative investigation of sleep has led to an important conclusion: It has suggested thatA) sleep serves an important physiological function.B) the function of sleep is not some special higher-order cognitive function.C) sleep may be essential for survival, but it is not necessarily required in large quantities.D) the amount of time that a members of a particular species tend to sleep is related to how long it takes them to consume enough energy when they are awake and how susceptible they are to predation when they are sleeping.E) all of the above