Which of the Following Is a Likely Explanation as to Why

Which of the following is a likely explanation as to why terrestrial animals do not have a skeleton built entirely of cartilage?

A) Cartilage grows quickly and must be replaced frequently, leaving organisms with a cartilaginous skeleton vulnerable to predators for most of their lives.
B) Cartilage is too porous to be used as a skeletal material on land. The numerous holes in this tissue would lead to rapid water loss from the body.
C) Terrestrial organisms require a living skeleton that can respond to environmental change. Cartilage does not contain cells and, therefore, cannot respond.
D) Cartilage is not as strong as bone and probably cannot support the weight of the body against the pull of gravity.