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Birth
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Lift head up on stomach
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Roll over
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Reaches for objects
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Sit with support
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Objects disappear when not in sight
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Sit without support
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Pull self up to standing position
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Walk holding on to furniture
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Object permanence
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Crawling
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Stand alone
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Walking
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Begins to move toward word of thought
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egocentric thinking and representational thought
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reversibility and conservation skills
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reversibility well established
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conservation skills and classification skills improve
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see world from other perspectives
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think abstractly and symbolically logical and deductive reasoning
