Which of the following is made up of smooth muscle tissue?

A. T-helper cells (CD4+ cells) play a crucial role in initiating and coordinating the immune response. They stimulate the activation of B-cells to produce antibodies and help activate cytotoxic T-cells to target infected cells.

B. The first line of defense against infection is provided by physical barriers like the skin, mucous membranes, and innate immune responses, not by T-helper cells.

C. While T-helper cells can activate macrophages indirectly by releasing cytokines, their primary role is in helping to activate other immune cells like B-cells and cytotoxic T-cells, rather than directly activating macrophages.

D. T-helper cells are not directly involved in minimizing cell damage caused by T-cells. That role is more closely related to regulatory T-cells (Tregs) that help maintain immune tolerance and prevent excessive immune responses.

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.