What is the primary form of carbon dioxide transported in the bloodstream?*1 pointCarbonic acidBicarbonate ionsDissolved carbon dioxide in plasmaCarbaminohaemoglobin

The primary form of carbon dioxide transported in the bloodstream is Bicarbonate ions.

Here's a step-by-step explanation:

1. When carbon dioxide (CO2) is produced as a waste product in cells, it diffuses out of the cells and into the bloodstream.
2. In the bloodstream, some of the CO2 can dissolve directly into the plasma. However, this only accounts for about 7% of the CO2 transport.
3. A small amount of CO2 can bind directly to hemoglobin to form carbaminohaemoglobin. This accounts for approximately 23% of the CO2 transport.
4. The majority of CO2 (about 70%) in the bloodstream is transported as bicarbonate ions (HCO3-). This happens through a series of reactions. First, CO2 combines with water (H2O) in the presence of an enzyme called carbonic anhydrase to form carbonic acid (H2CO3). This carbonic acid then quickly dissociates to form a hydrogen ion (H+) and a bicarbonate ion (HCO3-).
5. The bicarbonate ions then diffuse out of the red blood cells and into the plasma, where they are transported to the lungs. In the lungs, the reactions are reversed, and CO2 is exhaled.

So, the primary form of carbon dioxide transported in the bloodstream is as bicarbonate ions.