B.lack of water.
Lack of water is a changing external condition that triggers thirst.When a person is dehydrate, there is deficiency of water in his/body. This prompts the desire to take in more fluid to supplement the water. This leads to thirstiness in which the mouth becomes dry. Urine changes color showing lack of water. This stimulates the subject to want more water. Lack of water, dehydration, triggers thirst.
Lack of water triggers thirst.
The lack of water in the external environment creates an urge to drink water. The mind sends the signal that there is a loss of water from the body and it is dehydrated. This signals is recognized by the body and water is taken after this signal. The human body is made up of 70% of water and is vital for performing various functions of the body. Dehydration of water can led to several problems. The human body should not wait for the signal associated to dehydration and 4-5 liters of water must be taken daily.
The correct answer is lack of water.
The external condition which triggers thirst is because there is lack of water. Thirst is termed as the craving fluid which results with a major instinct of animal to drink.
It is a mechanism which is essential in balancing of fluid. When there is low volume of water in the body then the osmolite concentration goes high then the brain signals thirst.
When body is being dehydrated it is when we feel thirst. When there is no proper amount of water in the body or excessive thirst it can results to diabetes mellitus which is high blood pressure.
The correct answer is option D, change in temperature
The climatic change affects all our metabolic processes. During winter when the temperature is low, the daily rate of dehydration becomes extremely low in our body and thus, the rate of sweating also reduces due to which the requirement of water in our body gets minimal.
While in summer, when the external temperature is at its peak condition, the rate of dehydration becomes extremely high and thus the rate of sweating increases which in turn enhances the requirement of water in our body as we get thirsty very fast.
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