How many molecules of $H_2CO_3$ are formed due to the presence of carbonic anhydrase in the cytoplasm every second?

State the different modes of $CO_{2}$ transport in blood.

Which is the respiratory pigment or oxygen carrier in frogs?

Given below are two statements:
Statement $I$: The relationship between $HbO_2$ saturation and oxygen tension $(pO_2)$ is called the oxygen-dissociation curve.
Statement $II$: The oxygen dissociation curve shifts towards the right due to a decrease in $ppCO_2$ and a decrease in temperature.
In the light of the above statements,choose the most appropriate answer from the options given below.

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

How much oxygen is delivered to the body tissues by blood during one circulation (in $\%$)?