Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

[EX Q]: Question: What type of shape does a pelvic inlet have? Answer: oval shape
[EX A]: Pelvic inlet has a round or oval shape.

[EX Q]: Question: Most ecosystems are disturbed too often to attain what final, stable status? Answer: climax community
[EX A]: Most ecosystems are disturbed too often to attain a final, stable climax community.

[EX Q]: Question: What always has the same elements in the same ratio? Answer: compound
[EX A]:
A compound always consists of the same elements in the same ratio. If the same elements combine in different ratios, they form different compounds.