blood and oxygen
That would be blood.
Yes. Plague-carrying fleas fed on humans, and the plague germ got into their blood.
Carbon dioxide in humans is mostly carried in the blood as bicarbonate ions (HCO3-). This process occurs in red blood cells where carbon dioxide combines with water to form carbonic acid, which then dissociates into bicarbonate ions and hydrogen ions. Around 70% of carbon dioxide is transported this way in the blood.
oxygen is carried in the blood vessels through the blood stream and to the corners of your body. you cannot live without oxygen. that's why it is important
blood is carried in the blood vessels.
Humans got infected by fleas(who carried the virus) who traveled on rats. Because of poor health conditions the fleas contacted humans and when they bit the humans their infected blood infected the human host.
Because the Aztecs thought that Huitzilopochtli (chief god) required human blood for survival.
oxygen is carried in red blood cells
Haemoglobin, oxygen, and iron are carried by blood cells.
Oxygen is transported in the blood
Blood carried by the pulmonary arteries is deoxygenated. Blood carried by the pulmonary veins is oxygenated.
The circulatory system is important to humans because the main components are the heart, the blood, and blood vessels.