求问argument第一题的提纲

gabonUID: 3265783

1.Woven baskets characterized by a particular distinctive pattern have previously been found only in the immediate vicinity of the prehistoric village of Palea and therefore were believed to have been unique to the Palean people. Recently, however, archaeologists discovered such a "Palean" basket in Lithos, an ancient village across the Brim River from Palea. The Brim River is very deep and broad(3), and so the ancient Paleans could only have crossed it by boat(1), but there is no evidence that the Paleans had boats. And boats capable of carrying groups of people and cargo were not developed until thousands of years after the Palean people disappeared. Moreover, Paleans would have had no need to cross the river(5)—the woods around Palea are full of nuts, berries, and small game(4). It follows that the so-called Palean baskets were not unique to Palea(2).

4.The fact that there are abundant resources currently does not indicate that those resources also existed in Palean times. (C→P) ★★★
5.        Other reasons other than food shortages may well result in the migration of a culture. (I.E) ★★★

怎么觉得4、5点根本就不搭嘎啊？？