Which components are part of the formed elements of blood?

The correct answer, which identifies the formed elements of blood, encompasses erythrocytes, leukocytes, and platelets. Erythrocytes, or red blood cells, are responsible for transporting oxygen from the lungs to the body's tissues and returning carbon dioxide back to the lungs. Leukocytes, or white blood cells, play a critical role in the immune system by defending the body against infections and foreign substances. Platelets are small cell fragments essential for blood clotting, helping to prevent excessive bleeding when injuries occur.

In contrast, the other options do not represent the formed elements of blood. Proteins, lipids, and carbohydrates are macromolecules essential for various bodily functions, but they are not classified as formed elements. Plasma, hormones, and nutrients refer to components of blood or its liquid matrix but are not the cellular elements that make up blood. Gamma globulins and serum involve specific proteins in the blood, with serum being the liquid component obtained after coagulation, but again, they do not include the cellular components that are categorized as the formed elements.

Understanding the distinction between these components is crucial for comprehending blood composition and its various functions in the human body.