In which form is $CO_2$ mostly carried by blood?

When temperature decreases,the oxyhaemoglobin dissociation curve will become:

Where is the enzyme $Carbonic \text{ } Anhydrase$ found in high concentration?

Identify the correct group of statements:
$I.$ Oxygen is carried by haemoglobin
$II.$ Oxygen is carried by carbonic anhydrase
$III.$ $CO_{2}$ is carried by haemoglobin
$IV.$ $SO_{2}$ is carried by haemoglobin
$V.$ Only oxygen is transported by the blood
$VI.$ Only $CO_{2}$ is transported by the blood
Choose the correct option.

Refer to the following statements:
$I$. Carbonic anhydrase is present in the erythrocytes.
$II$. In erythrocytes,the carbon dioxide combines with water and is transported.

In mammals,how much $CO_2$ is transported as bicarbonates of sodium and potassium in the blood?