判断

任何数都没有最大的倍数

    Elephants are the largest living animals on land. More than 500 1 kinds of elephants were found on the earth over the last 55 million years. Only 2 kinds are still alive today: the African elephant and the Asian (or Indian) elephant. These elephants can only be found in 3 places. However, the older kinds lived in cold places a long time4. An example is the mammoth (猛犸象) — the largest hairy elephant.

    The mammoth was the largest living elephant, which was about seven tons. 5 the elephants today, mammoths had black or dark brown hairs 6their bodies. All the mammoths had tusks (长牙).

    Scientists found most of the extinct (灭绝的) animals by 7 the fossils, 8 their bones and teeth that could be found. However, mammoths are quite different. During the Ice Age, mammoths died and were covered 9 in the ice. The ice kept them very well. So scientists could find the 10 body of the mammoth.

在等差数列$\left\{a_n\right\}$中，已知$a_1+a_2+a_3+a_4+a_5=20$，那么$a_3$=

①年轻人更具超前消费的理念      ②消费的升级决定产品的转型

③抓住核心消费群体可能致胜      ④消费的变化引导生产的调整

表层土的养分来自腐烂的动植物的遗体，它们被称为____。