Help please and answer A-D

A: Label each wave above as transverse or longitudinal.
B: Which wave above could be used to represent a sound wave?
C: Which wave above is used to represent an electromagnetic wave?
D: Which wave above is also a model for light waves?

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.

14,16 18 reacts with group