The worldwide record of earthquake activity indicates that . a. the frequency of activity is stable (constant)
b. the frequency of activity is diminishing
c. the frequency of activity is slowly increasing
d. the frequency of activity is increasing rapidly

My answer is d. hope this'll help

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.