What substance in blood that carries carbon dioxide?

Answer 1

Hemoglobin/haemoglobin (two different spellings of the same thing). It's a protein made up of four separate protein chains, each of which has a heme group, which has as its central feature a porphyrin ring containing an iron atom. This is what gives red blood cells their characteristic color (which is actually more of a dark purple than red when carbon dioxide is bound to the heme groups).

Answer 2

Some carbon dioxide can bind to the hemoglobin in red blood cells forming a compound called carboxyhemoglobin. Most carbon dioxide, however, gets transformed into a product called bicarbonate ion which is more soluble in the blood than carbon dioxide.

Answer 3

The substance in blood that carries carbon dioxide is called bicarbonate ions. Carbon dioxide is transported in the blood either dissolved in plasma or bound to hemoglobin in red blood cells, or in the form of bicarbonate ions.

Answer 4

Carbon Dioxide is carried by hemoglobin just like Oxygen. Some of it however is converted into bicarbonate which is unbound in blood.