Cells because most living things like plant life and humans are made up of cells and animals are made up of cells too!
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Changes in the environment may leave individuals less well adapted to compete successfully for resources such as food, water and mates. Sometimes an entire species may become unable to compete successfully and reproduce. These problems can lead to extinction.
Answer:
Animals preserve play very important role in maintaining ecosystem biodiversity. In animal preserves, animals are protected from the harmful effects of the changes which occur in the environments due to human intervention. In animal preserves,
animals should be kept in proper environment and provide a proper place for living and food in order to increase the population of the animals.