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Short-spined sea urchin fossils were found directly above long-spined sea urchin fossils in a layer of rock. What do the differences between the two sets of sea urchin fossils suggest about them?

The longer spines developed as the shorter-spined sea urchins grew older.
The longer-spined sea urchins existed before the shorter-spined sea urchins.
The shorter-spined sea urchins stretched their spines to ward off predators.
The shorter spines did not protect the sea urchins well enough and they died off.

User Momvart
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2 Answers

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Answer: it shall be opion b

Step-by-step explanation:

User Jwehrle
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2 votes

Answer:

The longer-spined sea urchins existed before the shorter-spined sea urchins

Step-by-step explanation:

The lower buried is what died off first and the recently buried is the newly evolved version.

User Icelemon
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