Answer:
It attempts something else to reach the same end product.
Plants cell unable to do photosynthesis use the reaction from our cells creating ATP. There are some other examples I'm sure but I can't remember them of the top of my head.
Answer:
Eggshells are made of calcium carbonate. If you soak an egg in vinegar the eggshell will absorb the acid and break down, or dissolve. The calcium carbonate will become carbon dioxide gas, which will go into the air.
Explanation:
It will bounce.
I believe that it is testable because you can do it at home.
Independent variable is vinegar.