What are the advantages and disadvantages of having a sacred text, rather than a human leader, serving as the Sikh guru?

What are the advantages and disadvantages of having a sacred text, rather than a human leader, serving as the Sikh guru? Which do you think is more effective?
Discuss the influence of Hinduism and Islam on Sikhism. Select and describe one characteristic of each religion that is found in Sikhism.
Research the Sikh gurus and select one guru other than Nanak. Explain at least two contributions your chosen guru made toward the development of the Sikh religion.