A) At high altitude the air sacs do not function
B) There is little oxygen in the atmosphere at high altitudes
C) At high altitudes birds flap their wings faster
D) There is little carbon dioxide at high altitudes
A) At high altitude the air sacs do not function
B) There is little oxygen in the atmosphere at high altitudes
C) At high altitudes birds flap their wings faster
D) There is little carbon dioxide at high altitudes