ALL OF THE ABOVE.
The orderly arrangement of notes of the chromatic scale in particular order for use within a musical piece is called A TONE ROW, A SERIES, OR A TWELVE-TONE TECHNIQUE.
Leonardo da Vinci was well known for bringing proper anatomy into the landscape of art. He had painstakingly perfected human anatomy through somewhat gruesome studies. The artist performed more than 10 human dissections in attribution to his work, becoming familiar with proportions and how the body should be drawn. From his findings, other artists were able to study his published notes and works for reference.
Best of luck! :)
Because he's not smart. No it isn't a hard desicion because he isn't smart