Eventually, everyone must sleep due to our (1 point) need for mental rest. beta waves. biological rhythms. delta waves.

Out of the available answers, the most likely correct would be that eventually everyone must sleep due to our need for mental rest. However, it is not as simple as this, as all of the processes implicated with mental rest (including the restoration of biological rhythms as mentioned in an alternative answer) cannot necessarily be summed up in this way.

Temperature and pressure