Two early signs of dehydration are thirst and dark-coloured urine. This is the body's way of trying to increase water intake and decrease water loss. Other symptoms may include: 1  dizziness or light-headedness. 2  headache. 3  tiredness. 4  dry mouth, lips and eyes. 5  passing small amounts of urine infrequently (less than three or four times a day).
Diurnality is a form of plant or animal behavior characterized by activity during the day, with a period of sleeping, or other inactivity, at night. The common adjective used for daytime activity is diurnal. The timing of activity by an animal depends on a variety of environmental factors such as the temperature, the ability to gather food by sight, the risk of predation, and the time of year.
The rhythms follow a roughly 24-hour cycle linked to the patterns of light and dark in the environment around the organism. Humans are no exception, with processes and behaviours such as sleep, cell division, and alertness following this 24-hour cycle.nimals and plants have rhythms that match these cycles. A simple example of this is activity linked to day and night. Kiwi are active at night; behaviour that is described as nocturnal. PÅ«keko are active during the day; behaviour that is described as diurnal.