Which is the respiratory pigment or oxygen carrier in frogs?

$100 \ ml$ of oxygenated blood contains:

$A$ major percentage $(97 \%)$ of $O_{2}$ is transported by RBCs in the blood. How is the remaining percentage $(3 \%)$ of $O_{2}$ transported?

$I.$ Increased partial pressure of $O_{2}$
$II.$ Increased partial pressure of $CO_{2}$
$III.$ Increased partial pressure of $H^{+}$
$IV.$ Decreased partial pressure of $O_{2}$
All the above situations favour the dissociation of oxyhaemoglobin except:

What happens to the oxygen-hemoglobin $(O_2-Hb)$ dissociation curve when the temperature decreases?

Oxyhaemoglobin is an unstable compound because