Like this study set? Create a free account to save it.

Sign up for an account

Already have a Quizlet account? .

Create an account


An endothermic vertebrate that lays eggs and has feathers and a four-chambered heart.

contour feather

A large feather that helps give shape to a bird's body.

down feather

A short, fluffy feather that traps heat and keeps a bird warm.


An internal organ of many birds that stores food inside its body after swallowing it.


A muscular, thick-walled part of a bird's stomach that squeezes and grinds partially digested food.


The difference in pressure between the upper and lower surfaces of a bird's wings that produces an upward force that causes the bird to rise.


An endothermic vertebrate with a four-chambered heart and skin covered with fur or hair, that feeds its young with milk from the mother's body.


A large muscle located at the bottom of a mammal's rib cage that functions in breathing.


A mammal that lays eggs.


A mammal whose young are born at an early stage of development, and which usually continue to develop in a pouch on their mother's body.

gestation period

The length of time between fertilization and birth of a mammal.

placental mammal

A mammal that develops inside its mother's body until its body systems can function independently.


A membrane that becomes the link between the developing embryo or fetus and the mother

mammary gland

An organ in female mammals that produces milk for the mammal's young.

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

Voice Recording