Which of the following elements is necessary for normal thyroid function?

A. An increased pulse is a later symptom of dehydration, as the body attempts to maintain blood pressure and circulation when fluid levels are low.

B. Poor skin turgor is a sign of more advanced dehydration and is usually detected when skin remains tented after being pinched.

C. Decreased urinary output typically occurs as dehydration progresses and the body conserves water, but it is not usually the first sign.

D. Thirst is one of the earliest and most common symptoms of dehydration, as the body signals the need for water intake to restore fluid balance. This is the correct answer.

A. The peripheral nervous system is responsible for transmitting signals between the central nervous system and the rest of the body, but it does not directly govern the increase in peristalsis.

B. The central nervous system (CNS) processes information and coordinates responses but does not directly control the movement of the digestive system. The autonomic nervous system, which includes the parasympathetic and sympathetic divisions, controls peristalsis.

C. The parasympathetic nervous system is responsible for "rest-and-digest" activities. It stimulates peristalsis to promote digestion and the movement of food through the gastrointestinal tract, leading to an increase in peristalsis.

D. The sympathetic nervous system is involved in the "fight-or-flight" response, which inhibits digestive processes, including peristalsis, as the body prioritizes other functions.