What trait is unique to mammals?
A. Feathers
B. Mammary glands
C. Legs
D. Amniotic egg
Do amphibians have amniotic eggs?
yes
no
What organisms are birds most closely related to?
Mammals
Reptiles
Amphibians
Fish
What trait separates fish from amphibians?
A. legs
B. amniotic egg
C. feathers
D. mammary gland