This quiz is about training your hearing. Learn to recognize and differentiate intervals. In music theory, an interval is the difference in pitch between two tones.
The interval of a major third corresponds to 4 semitone steps.
The minor third only has 3 semitone steps. The frets on the fingerboard correspond exactly to semitones.
In a major chord, such as C major, which consists of the notes C, E and G, the lower two notes C and E are a major third apart. From E to G is a minor third. The basic form of the major chord consists of a major third and a minor third above it. The interval from C to G is a fifth. But there is a separate video for that.
With a minor chord, such as C minor, which consists of the notes C, Eb and G, it is exactly the opposite. First there is a minor third at the bottom, from C to Eb. The top two notes Eb and G are now a major third apart.
Listen, play along, learn to recognize intervals, train your hearing! There are 4 rounds with 4 intervals each. Good luck, have fun!