In lungs,in order to facilitate the removal of $CO_2$ from the blood,there is an exchange of ions between $RBC$ and the plasma which involves the movement of:

Haemoglobin $(Hb)$ transports oxygen from the lungs to tissues. The partial pressure of oxygen in the lungs is different from that in the tissues. Each $Hb$ can bind to up to four oxygen molecules. Suppose we have an equal number of $Hb$ and oxygen molecules,and all the oxygen molecules are in a bound form. Then,which of the following is true?

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.

In blood,the majority of $CO_2$ is transported by which of the following?

Body tissues obtain $O_2$ from hemoglobin. The dissociation of oxyhemoglobin in the tissues is primarily caused by which of the following conditions?

Which respiratory pigment is responsible for transporting oxygen from the blood to the tissues in vertebrates?