What combination of factors can change dry ice into a liquid

When dry ice is heated, it rapidly forms carbon dioxide gas. This gas is fairly cold. So when the cold CO2 gas is released, it causes water vapor in the air to condense. You see this condensed water.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.