Choose from:
1). the researchers reached their conclusion by analyzing the data;
2). the research centered on the 26 types of behavior of the matriarch;
3). the scientists conducted the research by comparing elephants with other animals;
4). professor Phyllis Lee and her colleague spent nearly 38 years tracking the herd;

Read the following article and answer the question. Article: Elephants have four distinct personalities that help their herd survive in the African bush, scientists have found. With their grey skin, mournful eyes and slow heavy pace, you could be forgiven for thinking elephants are uniformly melancholy creatures. But scientists have now discovered the largest living land animals have personalities to match their size. In a new study of African elephants, researchers have identified four distinct characters that are common in a herd - the leaders, the gentle giants, the playful rogues and the reliable plodders . Each of the types has developed to help the giant mammals survive in their harsh environment and is almost unique in the animal kingdom, according to the scientists. Professor Phyllis Lee and her colleague Cynthia Moss studied a herd of elephants in the Amboseli National Park in Kenya known as the EB family -- famous for their matriarch Echo before she died in 2009. Using data collected over 38 years of watching this group, the researchers analyzed them for 26 types of behavior and found four personality features tended to emerge. The strongest personality to emerge was that of the leader. Unlike other animals, where leadership tends to be won by the most dominant and aggressive individual, the elephants instead respected intelligence and problem solving in their leader. Echo, the matriarch and oldest in the group, her daughter Enid, and Ella, the second oldest female, all emerged as leaders. The playful elephants tended to be younger but were more curious and active. Eudora, a 40-year-old female in the herd, seemed to be the most playful, consistently showing this feature throughout her life while playfulness in some of the other elephants declined with age. Gentle elephants, which included two 27-year-old females Eleanor and Eliot, touched and rubbed against others more than the others. Those that were reliable tended to be those that were most consistent at making good decisions, helped to care for infants in the herd and were calm when faced with threats.... Question: From the passage we get to know that _ . Answer:
Answer:
1).