Answer:
1. The appearance and disappearance of fossils.
2. major physical changes on the earth's surface.
The correct answer is <span>d.think through a series of steps and then mentally reverse direction.
Reversibility is the understanding and awareness that mental or physical operations can be reversed. For instance if a task requires eight sequential steps to be completed, a child who is capable of reversibility will be aware that the eight steps can be reorganized or reversed and/or replaced by a different set of steps. </span><span>
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Answer:
Ya mothers are our life happy mother's day to all the mothers:)