What were official "memorizers" in the Inca empire required to do and why?

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.

while it was true that the cotton gin reduced the labor of removing seeds, it did not reduce the need for slaves to grow and pick the cotton.

explanation:

before eli whitney's invention of the cotton gin, picking and cleaning cotton was a slow, labor-intensive job. workers, usually slaves, had to pick the seeds from the cotton fibers by hand. this invention made it possible to grow large amounts of cotton on big farms and make money.

dylan has written many enduring songs and he has received several awards for his musical achievement;  

any written work with artistic value can be considered literature; especially if such work is publicly recognized, and has had importance and endurance among people; whether is poetry or fiction or drama or even criticism, since it's the transcendence and representation of a culture, language or people in a period of time to more people, using letters (words), regardless the subject.

the nobel prize in literature is given to authors from any country based on a body of work as a whole that inspires and nurses the life of humanity.  

and the work of bob dylan matches that description, therefore is well deserved since he'd created new poetic expressions within the american song tradition, that has inspired and influenced the lives of many people, not only withing the united stated but worldwide as well.