Join Clutch Prep
Access over 20 thousand video solutions for chemistry
Already have an account? Log In
All of the following are unique (only found in) avian characters, EXCEPT:
a. Four-chambered heart
b. Air sacs
Don't have an account? Sign up!.
If you forgot your password, you can reset it.
Join thousands of students and gain free access to 23 hours of Biology videos that follow the topics your textbook covers.