How does carbon-14 form? A. Neutrons from space collide with nitrogen atoms in the air.
B. When 2 standard carbon-12 atoms collide with each other and fuse.
C. They are only formed inside stars.
D. When a standard carbon-12 atom is struck by gamma radiation.

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.

hurricanes form in warm water

it is stable as it is in group 0 which have full outer shells of electrons