In this task, you are given a question and answer for that. The answer will fill in the blank or will complete the unfinished question. Your task is to provide an explanation based on the given question or fill-in-the-blank statement, and answer.

Q: Question: Simon was digging in his yard and found that the rocks that were shallower in the ground, compared to the surface rocks, were likely 
 Answer: younger

A: Therefore, deeper rock layers must be older than layers closer to the surface.
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Q: Question: Exponential growth of a population of animals means it 
 Answer: increases

A: With exponential growth, the population starts out growing slowly. As population size increases, the growth rate also increases.
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Q: Question: The darker someone's skin is the _____ melanin they have. 
 Answer: more

A:
However, the melanocytes of people with darker skin produce more melanin.
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