iBT TOEFL Topic Vocabulary Breakthrough Unit 071

iBT TOEFL Topic Vocabulary Breakthrough Unit 071
Author: Li Xiaolai

71. Ant colonies have elaborate social structures in which the various activities necessary for the feeding, shelter, and reproduction of the colony are divided among specially adapted individuals. Ants belong to an order of insects called the Hymenoptera, a group that also includes bees, wasps, and sawflies. Some species of wasps and bees resemble ants in that they live in colonies and are therefore said to be social, but ants are the only hymenopterans in which every species is social. Ants are distinguished from other hymenopterans in that they have bent, or elbowed, antennae and an indented abdomen that forms a narrow waist.

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