Which components make up blood?

Blood is composed of several key components that are essential for its functions in the body. The correct answer identifies these components as red blood cells, white blood cells, platelets, and plasma.

Red blood cells are responsible for transporting oxygen from the lungs to the rest of the body and returning carbon dioxide from the body back to the lungs for exhalation. White blood cells play a crucial role in the immune system, helping to defend the body against infection and disease. Platelets are involved in the clotting process, which is essential for stopping bleeding following injuries. Plasma, the liquid portion of blood, serves as a medium for transporting various substances throughout the body, including nutrients, waste products, hormones, and proteins.

The other options listed either refer to non-blood components or include broader categories that do not specifically pertain to the composition of blood itself. Muscle fibers, hormones, enzymes, and nutrients, for instance, are important in various bodily functions but are not components of blood. Similarly, while plasma, lymph, and interstitial fluid are fluids in the body, only plasma is a component of blood. Cells, tissues, organs, and systems encompass the broader biological hierarchy but do not specifically detail the makeup of blood.