I'm not sure, but it might be haemoglobin? I think. :-)
Unlike mammals who absorb oxygen through the alveolar in their lungs, frogs are able to use their skin as a surface for gas exchange. The capillaries carry oxygen poor blood underneath the skin so that the oxygen in the air or water will be transported into the blood.
Oxygen is necessary for a substance to burn. It reacts with the substance in a chemical reaction known as combustion, releasing heat and light energy. Without oxygen, the substance will not be able to sustain a fire.
Cnidarians are able to absorb the oxygen they need from the surrounding water by diffusion.
POtatos <==That is not correct, idiots!
The function of blood in circulatory is to bring oxygen to the cells around the body. Without blood cells would not be able to get oxygen.
When oxygen enters the body, it is carried to the cells by red blood cells. These red blood cells contain hemoglobin, a protein that binds to oxygen in the lungs and transports it to tissues throughout the body. Once oxygen-rich blood reaches the cells, it is able to participate in cellular respiration to produce energy.
The alveoli is the point where the waste product of respiration (carbon dioxide) and oxygen are diffused into or out of the blood. Oxygen diffuses into the blood stream and are carried to the heart and carbon dioxide is diffused out of the lungs and expired. The alveoli have moist walls and are close to the capillaries which speeds up the process.
This isn't a definite answer but blood probably goes slower when it travels through capillaries, this is probably because it is basically being filtered.
Get oxygen to your muscles
It's not really the blood that needs the oxygen. All the living tissues in our bodies needs a steady supply of oxygen, and the blood is what carries that oxygen around and delivers it where it needs to go.
The oxygen in each breath is circuited to the lungs where the alveoli absorb the oxygen and passed to the blood cells. The blood cells enter the heart where the oxygenated blood is circulated where needed.
because your blood carries oxygen to you muscles. without much oxygen blood won't be able to take lots to your muscles, and with little oxygen your muscles won't work as well and therefore you won't run as quickly :)