Read the following text to answer questions 4 to 8.

   Dani is a general name for all tribes of the Baliem Valley in Papua. The origin of these people is not known. They all have dark brown skin, but each tribe's language and customs are different. They use bird feathers, cowry shells, and a special kind of wood for trading.

   The Dani are farmers. They have been farmers for at least 5,000 years. They are very skilled farmers. They raise pigs and grow sweet potatoes. They spend most of their time working on their farms. As a result, they are very physically fit and strong.

    Everybody who meets the Dani people say that they are fearless. They are afraid of nothing or nobody. On the other hand, everybody says that they are very friendly. 

Source: English for Communication SMP 3 

What does the text tell us about?