What discovery did the study of fossil horse teeth lead scientists to make? Early horses had a generalized diet of hard food items, including twigs.

Early horses had a specialized diet of grass, a soft food item.

Early horses had a specialized diet of bark, a hard food item.

Early horses had a generalized diet of soft food items, including leaves.

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.

i believe the answer is a.