What is the percentage of $O_2$ transported in dissolved form through the plasma?

With which part of $Hb$,$O_2$ molecules bind?

Name the enzymes $A$ and $B$ in the following equation:
$CO _2+ H _2 O \underset{B}{\stackrel{A}{\rightleftharpoons}} H _2 CO _3 \underset{B}{\stackrel{A}{\rightleftharpoons}} HCO _3^{-}+ H ^{+}$

Identify the incorrect statement regarding the transport of oxygen:

The toxic effect of carbon monoxide is due to its greater affinity for haemoglobin as compared to oxygen by (approx.) (in $\times$)

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