That would be either, nuclear power or wind power, depending on what the teacher is looking for...
Explanation:
The given reaction is redox reaction but not combustion reaction.
Redox reaction : It is a chemical reaction in which oxidation and reduction occurs simultaneously.Oxidation is gaining of electrons and reduction is loosing of electrons.
oxidation
reduction
Potassium when reacts with water ,gives potassium ion in aqueous medium and combines with hydroxide ion present in water to form potassium hydroxide where as 
ions of water by gaining electrons (from potassium in water) gives hydrogen gas.
Hence , yes it is a redox reaction
Combustion reaction are the chemical reaction in which one reactant react with oxygen molecule to give heat and light.
Here in given reaction no oxygen molecule is appearing on reactant side.
Hence not a combustion reaction.
Answer:
40 g
Explanation:
Find the line labeled KClO3 (which might take you a min, theres a lot of lines here)
Notice that when the line creates a direct point, you can measure the exact temperature needed to dissolve a certain amount (like how they gave 30 degrees and it lined up perfectly with the 10 g line. )
Since its asking for the amount at 80 degrees, all you need to do is trace the line to the 80 degree point, and look at the grams. (notice it made a direct point, so there definitely should be any decimals or guesswork)
By reading the graph, you can tell that at 80 degrees, it dissolves 40 grams, and that is your answer.
Hope this helps :)
The answer is D the oldest layer
