Migration is seasonal movement of animals from one region to another. A nomad is someone who has no personal home, and they travel from place to place for a variety of factors like crops and fresh pasture for livestock.
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By population which is determined by the census conducted every ten years. (each state has at least one representative)
Natural Selection, or human adaptations through evolution.
Today's technologies<span> allow us to </span>explore the ocean<span> in increasingly </span>
