Remove the tank cover and check the water level after the fill valve has shut off. It should be about one inch below the opening of the overflow tube. If it is significantly lower than that, there may not be enough water in the tank to fill the bowl after a flush. Correct this by adjusting the float.
The average child can do this during the second half of this year. Between 24-36 months, children are typically able to work simple insert puzzles (e.g., completes a three-piece simple puzzle where pieces are whole objects). Also, children can remove a part from a toy (e.g., a wheel) and replace it.
One of the unique talents that mark us as humans is our ability to express our thoughts to others in a way that can be understood, even if the subject is complex and abstract. Thus it is not surprising that scholars have struggled for centuries to understand how an infant can learn language in an incredibly brief period. It begins with a single word, like Da or Ma.. A few days later, it seems, they are asking for the keys to the family car. No other animal on the planet can do that.