Which of the following factors are favourable for the formation of oxyhaemoglobin in alveoli?

What conditions in the tissues favor the formation of carbaminohemoglobin?

Exposure to carbon monoxide (from coal gas) is extremely dangerous and can kill a patient because

Oxyhaemoglobin can transport

The following statements refer to the transportation of gases. Read them carefully and choose the correct option containing the incorrect statements.
$(i)$ After leaving the lungs, each litre of blood contains about $20 \ ml$ of oxygen.
$(ii)$ When $PCO_2$ rises, the affinity of haemoglobin for oxygen is increased.
$(iii)$ Each litre of arterial blood contains about $4 \ ml$ of $CO_2$.
$(iv)$ The role of oxygen in the regulation of respiratory rhythm is quite significant.

Select the correct option for the transport of $CO_2$ in the blood:
$RBCs \quad Plasma \quad Bicarbonate$