Given a scientific question, generate a correct answer to it.

Input: Consider Input: Most vascular plants are seed plants, also known as?

Output: spermatophytes


Input: Consider Input: What is a primary source of the hormone melatonin?

Output: pineal gland


Input: Consider Input: The ordovician-silurian extinction event is the first recorded mass extinction and the second largest. during this period, about what percent of marine species went extinct?

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Output: 85 percent


