Chemical formula quiz 2.2.02

Look at a chemical formula, and then select an answer from four selected.
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In the ranking screen, you can check the high score of challengers around the world.
You can learn easily about chemical formiula.

Features:
We have the following features.
Retry the ability to re-challenge the problem you made a mistake.
Learning the ability to answer the questions 10-30 random.
History display function that can check the results of past.
Global ranking function that to the world the results of their own.
Search function to look for items from the correct result screen.