Explain the concept of dukha and its role in Buddhist teaching.

1. (Buddhism) Explain the concept of dukha and its role in Buddhist teaching. What would you say are the foremost differences and similarities of the three branches of Buddhism?2. Explain the holy book of Sikhism? What is its significance within Sikhism? Also add at least one thing you can appreciate or/and one thing you can criticize about Sikhism.