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  3. The oldest adult human skull yet found belongs to the lowest grade of Homo erectus, and to the Australoid line. It is known as P

The oldest adult human skull yet found belongs to the lowest grade of Homo erectus, and to the Australoid line. It is known as P

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问题     The oldest adult human skull yet found belongs to the lowest grade of Homo erectus, and to the Australoid line. It is known as Pithecanthropus (Ape-Man) Number 4, because it was the fourth of its kind to be found. All four were unearthed in river banks in central Java. Number 4 is about 700,000 years old, and Numbers 1,2, and 3 between 600,000 and 500,000. We know this because tektites--small, glassy nodules from outer space--were found in the same beds as the first three, and the beds containing Number 4 lay underneath the tektite bed, along with the bones of a more ancient group of animals. These tektites have been picked up in large numbers in Java, the Philippines, and Australia, where they all fell in a single celestial shower. Their age--approximately 600,000 years--has been accurately measured in several laboratories by nuclear chemical analysis, through the so-called argon-potassium method.
    Pithecanthropus Number 4 consists of the back part of a skull and its lower face, palate, and upper teeth. As reconstructed by Weidenreich, it is a brutal-looking skull, with heavy crests behind for powerful neck muscle attachments, a large palate, and large teeth, as in apes. The brain size of this skull was about 900 cubic centimeters; modern human brains range from about 1,000 to 2,000 cc with an average of about 1,450 cc. The brains of apes and Australopithecines are about 350 to 650 cc. So Pithecanthropus Number 4 was intermediate in brain size between apes and living men.
    His fragmentary skull was not the only find made in the beds it lay in. Nearby were found the cranial vault of a two-year-old baby, already different from those of living infants, and a piece of chinless adult lower jaw. Two other jaws have been discovered in the same deposits which were much larger than any in the world certainly belonged to a Homo erectus. They are called Meganthropus (Big Man) and may have belonged to a local kind of Australopithecine, but this is not certain, If so, Homo erectus coexisted with, or overlapped, the Anstralopithecines in Java as well as in South Africa, which implies that man did not originate in either place, but somewhere in between.
The age of prehistoric fossils can be determined by ______.
选项 A、nuclear chemical analysis
B、data left with the fossils
C、reconstructing the skull
D、external evidence in the ground in which the fossil is found
答案D
解析 史前化石时代是通过发现化石的岩层的外在的证据来决定的。4号猿人的时代取决于这样的事实，它是在一层玻陨石底下发现的。
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