Consider the reaction ${\mathrm{CaCO}}_{3\left(\mathrm{s}\right)}\iff {\mathrm{CaO}}_{\left(\mathrm{s}\right)}+{\mathrm{CO}}_{2\left(\mathrm{g}\right)}$ .According to the Le Chatelier's principle, decomposition of ${\mathrm{CaCO}}_{3\left(\mathrm{s}\right)}$ is favored by

Removal of ${\mathrm{CO}}_2$ at high temperature 

Adding ${\mathrm{CaO}}_{\left(\mathrm{s}\right)}$  at high temperature 

Removal of CaO at low temperature 

Adding ${\mathrm{CaCO}}_{3\left(\mathrm{s}\right)}$ at low temperature