$A$ large proportion of oxygen is left unused in the human blood even after its uptake by the body tissues. This $O_{2}$

Choose the incorrect sentence from the following.

If $ppCO_2$ is high and pH is low,then it will result in:
$i$. increase in affinity of haemoglobin for $O_2$
$ii$. decrease in affinity of haemoglobin for $O_2$
$iii$. oxygen dissociation curve shifts to left
$iv$. causes release of $O_2$ for diffusion into tissue cells
$v$. $H^+$ and $HCO_3^-$ ions combine to form carbonic acid

Carbonic anhydrase is found in .......... .

What does $Methemoglobin$ indicate?

The oxygen dissociation curve of hemoglobin is . . . . . . .