on September 25, 2019
I think the answer choices are out of order. For me, C says The ozone layer regenerates at a slow rate, barring counteractive processes." So B would be the correct answer because it talks about our ancestors having an extra layer of protection.
Irina on September 25, 2019
Margine on December 16 at 06:02PM
on May 14 at 10:47PM