Final answer:
Steven, being sleep-deprived, is likely to experience increased cortisol levels, so decreased cortisol is the effect he is NOT likely to experience. Sleep deprivation typically also leads to decreased focus, increased risk of depression, and a decreased metabolic rate. So the correct option is c.
Step-by-step explanation:
Steven has been sleep-deprived for most of his adult life, and he is likely to experience a range of detrimental effects due to this condition. However, the one effect he is NOT likely to experience is decreased cortisol. Sleep deprivation is known to lead to an increase in cortisol levels, not a decrease. Cortisol is often referred to as the stress hormone, and increased levels can be a response to the stress of being sleep-deprived. Conversely, sleep deprivation is associated with a decreased ability to focus attention, an increased risk of depression, and a decreased metabolic rate. Therefore, option C - decreased cortisol, is the correct answer, as it is an effect that is not typical of sleep deprivation.