Nervous/endocrine questions help pls!!

What causes darkening of the skin as melanin production increases

The graph below compares the rates of reaction of a burning candle and an exploding firework. comparing chemical reactions what can you conclude from the graph? the reaction that causes a firework to explode requires less energy to start, and occurs more rapidly than the reaction that causes a candle to burn. the reaction that causes a firework to explode requires less energy to start, and occurs less rapidly than the reaction that causes a candle to burn. the reaction that causes a firework to explode requires more energy to start, and occurs less rapidly than the reaction that causes a candle to burn. the reaction that causes a firework to explode requires more energy to start, and occurs more rapidly than the reaction that causes a candle to burn. mark this and return

Why is it incorrect to say that mitochondria function only as energy factories with cell