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.

[Q]: Question: Wings of bats and birds serve the same function. which body part should you study to understand ancestral differences? Answer: bones inside wings
[A]: Wings of bats and birds serve the same function. Look closely at the bones inside the wings. The differences show they developed from different ancestors.

[Q]: Question: The lungs, kidneys, skin, and large intestine are all part of what organ system? Answer: excretory
[A]: Organs of the excretory system include the kidneys, large intestine, skin, and lungs.

[Q]: Question: What are large glaciers that cover a larger area than just a valley? Answer: ice caps
[A]:
Ice caps are large glaciers that cover a larger area than just a valley. An ice cap can bury an entire mountain range or region ( Figure below ). Glaciers come off of ice caps into valleys.