Which can be explained as applications of Le Chatelier's principle?

(i) The haemoglobin of RBC combines with oxygen in lungs following the equilibrium, ${\mathrm{H}}_{\mathrm{b}}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\rightleftharpoons {\mathrm{H}}_{\mathrm{b}}{\mathrm{O}}_2\left(\mathrm{s}\right)$
When these are at lungs, the partial pressure of O₂ being appreciable to show forward reaction, however, when they pass to tissues, the partial pressure of O₂ decreases to favour backward reaction releasing O₂.
(ii) Removal of CO₂ from blood is based on the equilibrium, ${\mathrm{CO}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\rightleftharpoons {\mathrm{H}}^{+}\left(\mathrm{aq}\right)+{\mathrm{HCO}}_3^{-}\left(\mathrm{aq}\right)$
ln tissues CO₂ gets dissolved in H₂O due to high pressure whereas in lungs, the CO₂ is released out because of low pressure of CO₂.
(iii) Tooth enamel substance (hydroxyapatite) ${\mathrm{Ca}}_5{\left({\mathrm{PO}}_4\right)}_3\mathrm{OH}$ shows the following equilibrium, 
${\mathrm{Ca}}_5{\left({\mathrm{PO}}_4\right)}_3\mathrm{OH}\underset{ \mathrm{Remineralization} }{\overset{ \mathrm{Demineralization} }{\rightleftharpoons }}5{\mathrm{Ca}}^{2+}\left(\mathrm{aq}\right)+3{\mathrm{PO}}_4^{3-}\left(\mathrm{aq}\right)+{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)$
The use of sweet material or fermentation produceS H⁺, which combines with OH- to favour demineralization of enamel causing tooth decay.