an extinct group of reptiles from which mammals evolved
glands that make a nutritious fluid for embryos called milk
teeth used to cut food
teeth used to stab and slice teeth
teeth used to grind up food
a young mammal's first small teeth
a large muscle in mammals that helps bring air into the lungs
mammals that lay eggs
mammals with pouches in which the young go in for protection
Mammals that have embryos that develop in mother's uterus until its body systems can function independently
time in which embryo develops within the mother
Please allow access to your computer’s microphone to use Voice Recording.
We can’t access your microphone!
Click the icon above to update your browser permissions above 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.
Your microphone is muted
For help fixing this issue, see this FAQ.
NEW! Voice Recording
Click the mic to start.