What substance in red blood cells aids in oxygen transport?

Hemoglobin is the substance in red blood cells that plays a crucial role in transporting oxygen throughout the body. This protein has a unique structure that allows it to bind to oxygen in the lungs and release it in tissues where it is needed. Each hemoglobin molecule can carry four oxygen molecules, which significantly enhances the oxygen-carrying capacity of blood.

In contrast, platelets are involved in blood clotting and do not participate in oxygen transport. Myoglobin, while similar to hemoglobin, is found in muscle tissues where it functions to store oxygen for use during muscle contraction but does not carry oxygen in the bloodstream. Cholesterol is a lipid that is vital for cell membrane structure and hormone production but has no direct role in oxygen transport. Thus, hemoglobin serves as the essential component for oxygen delivery, making it the correct answer.