| A | B |
|---|
| chromosome | cell structure that carries genetic material that is copied and passed from generation to generation of cells |
| monotremes | mammals that reproduce by laying eggs |
| marsupial | pouched mammal that has a very short gestation period |
| placental mammal | mammal that has a placenta and gives birth to young that need no further development within a pouch |
| therapsid | extinct mammal like reptile from which the first mammals probably arose |
| chromosomes | cell structures that carry genetic material that is copied and passed from generation to generation of cells |
| monotreme | mammal that reproduces by laying eggs |
| marsupials | pouched mammals that have a very short gestation period |
| placental mammals | mammals that have a placenta and give birth to young that need no further development within a pouch |
| therapsids | extinct mammal like reptiles from which the first mammals probably arose |
