Given a scientific question, generate an incorrect answer to the given question. The incorrect answer should be a plausible alternative to the correct answer. The answer should be some other item belonging to the same category as the correct answer but should be incorrect.
One example: What are arteries, veins, and capillaries examples of?
Solution is here: tissue
Explanation: Blood vessels include arteries, veins, and capillaries. Tissue is a combination of cells.

Now, solve this: Varves form in lakes covered by what?
Solution:
coral reef