Oxygen transported through the bloodstream to the tissues is primarily attached to which of the following?

The transport of oxygen in the bloodstream to the tissues predominantly occurs through hemoglobin, a protein found in red blood cells. Hemoglobin has a high affinity for oxygen, allowing it to efficiently pick up oxygen in the lungs where oxygen concentration is high and release it to the tissues where oxygen levels are lower. This mechanism is essential for maintaining adequate oxygen supply throughout the body to support cellular metabolism and function.

Platelets are involved in blood clotting and do not play a role in oxygen transport. Myoglobin, while it binds oxygen, primarily functions within muscle tissues to store oxygen for use during muscle contraction, rather than transporting it through the bloodstream. Albumin is a protein that helps maintain osmotic pressure and transport various substances in the blood, but it does not carry oxygen. Therefore, hemoglobin is the key molecule responsible for the majority of oxygen transport in the circulatory system.