The most likely thing that happened with this poor young woman who broke her leg was that she broke hte bone at a very young age and that it fully healed. C
This is so because collagen is a substance that gets secreted at the point of fracture which helps strengthen the bone. Having a higher amount of collagen at the site of a broken bone means that the bone probably healed properly and there was a remainder of collagen to be found.
Answer: D. Extinctions occur at higher rates during times of ecological stress when populations and species are poorly adapted.
An enzyme, it catalyzes the reaction to convert carbon dioxide into carbonic acid