Final answer:
True, the extracellular fluid (ECF) has two main functions: maintaining a stable environment for cells and aiding in the transportation of materials to and from them, including nutrients and waste products.
Step-by-step explanation:
The statement that extracellular fluid (ECF) has two main functions—providing a relatively constant internal environment for cells and transporting materials to and from them—is true.
The ECF, consisting of bodily fluids like plasma and interstitial fluid (IF), plays a crucial role in maintaining the body's internal environment.
Plasma is a key component of the blood and is responsible for the transport of blood cells, proteins, electrolytes, nutrients, gases, and wastes.
It communicates freely with the interstitial fluid, which bathes and surrounds the body's cells, supplying them with nutrients and a means for waste removal.
The ECF acts as a buffer and helps to maintain the osmotic balance and the proper pH of the body, which is essential for cell survival and function.
The ECF also facilitates diffusion and active transport processes that allow cells to exchange substances such as gases, water, and small molecules with their surrounding environment, while large molecules like proteins are usually not permeable through the cell membrane without additional transport mechanisms.