Final answer:
Proteins regulate acid-base balance, fluid balance, and muscle contraction in the body, making all of the provided options correct. They attract fluid and transport electrolytes to ensure physiological homeostasis.
Step-by-step explanation:
Proteins serve critical functions in the human body, including roles in acid-base balance, fluid balance, and muscle contraction. Proteins function as buffers, maintaining the pH of blood and other bodily fluids within a narrow range. They also regulate fluid-electrolyte balance by attracting fluid, ensuring balanced fluid levels among blood, cells, and interstitial spaces. Furthermore, proteins are essential in cell membranes for the transport of electrolytes, maintaining ion balance, necessary for various physiological processes, including neural signal transmission and muscle contraction.
Hormones play a pivotal role in regulating the body's fluid and electrolyte balance. Aldosterone and angiotensin II control sodium and potassium exchange in the kidneys, while calcium and phosphate levels are regulated by PTH, calcitriol, and calcitonin. These mechanisms help maintain the essential osmotic balance and proper functioning of cells and tissues in the body.
The final answer in two line explanation in 300 words: Proteins regulate acid-base balance, fluid balance, and muscle contraction, thus all of these are correct. Their ability to attract fluid and transport electrolytes across cell membranes is pivotal for maintaining homeostasis in the body.