The correct answer is option 1: Potassium. Potassium is involved in the control of water content in the blood. It is an essential mineral that plays a crucial role in maintaining proper hydration in the body.
Potassium helps regulate the balance of fluids and electrolytes in the body by controlling the movement of water into and out of cells. It acts as an electrolyte, which means it carries an electric charge and helps conduct electrical impulses in the body. This includes the movement of water across cell membranes.
When potassium levels are too high in the blood, it can cause dehydration because excess potassium draws water out of cells, leading to increased urine production. On the other hand, low potassium levels can disrupt the body`s fluid balance and lead to water retention and swelling.
It`s important to note that while lithium, rubidium, and caesium are chemical elements, they are not directly involved in the control of water content in the blood. Therefore, options 2, 3, and 4 are incorrect.