The 2nd and 4th answer choices sound the best to me. I personally would go for the 2nd one, explaining that the fossils of fish K and fish R and Y are similar. If you get the question wrong, I am VERY sorry. :(
I think the answer is Releasing a black powdery substance on their trunks or shifting their range toward the poles.
Answer: it should be producer
The answer is
<span>D) hepatopancreatic ampulla
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