Which is typically one of the early symptoms of dehydration?

Symptoms of dehydration:
Thirst
Dry mouth
The pee being dark yellow
Fatigue
Headache
Muscle cramps
dry skin
dizziness
Rapid heartbeat
Rapid breathing
Sunken eyes
Sleepiness
confusion
Fainting

The earliest are probably the feeling of dry mouth and thirst.

Cell division is important to single celled organisms because it allows the cells to reproduce. through cell division, cells make exact copies of themselves. when single celled organisms go through cell division, they make exact copies of themselves which is how they reproduce.