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.
New born babies can see very little other than light and motion. At 3 months they can make out faces (and return your smile). By 6 months an infant can distinguish between objects, such as a bottle or a stuffed toy. By age 2 years, most children have about 20/60 vision (at 20 feet they can make out what a normal adult can see at 60 feet).