You call one of your friends to go to a movie on friday night. he declines your invitation, stating that he needs to study for his upcoming exam on monday. he states that he scores higher on a exam when he studies for the exam. despite your efforts to convince him to go to the movie, he stays at home to study for his exam. you decide to use the scientific method to test the hypothesis that students who study for an exam tend to score higher than students who do not study for an exam. in what order should you conduct the following steps to test your hypothesis?

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.

the answers would be

the first one and the second one

i think it's letter a.