TOEFL Reading: ETS-TOEFL阅读机经 - 1KV42S65E53JY2BHL$

According to paragraph 2, all of the following are true of the eggs of amphibians during the Mississippian epoch EXCEPT: A. They had hard shells made from calcium ions. B. They had larger yolks than previously. C. They had protective membranes. D. They were produced in larger quantities than previously.