Figure out what similarities the things have, and it should get more specific the lower you go. There should be 2 statements in each category. For example: 1a. has feathers (go to step 2) b. doesn't have feathers (go to step 3)
2a. swims (Duck) b. doesn't swim (Hen)
3a. has legs (Lizard) b. doesn't have legs (Snake)
