Flying
In order for birds to fly, they need lots of oxygen and their heart must pump that oxygenated blood. They have ____ chambers in their heart.
What is 4 chambers?
Flying is hard so the bones are _________
What is lightweight or nearly hollow?
The prominent ridge on the breastbone for attachment of flight muscles
What is the keel?
The powerful muscles needed for flight
What are pectorals?
The backbone of the flight feather
What is the rachis?