Classify each animal according to whether or not it has an internal sketeleton .
Classify each animal according to whether or not it has an internal sketeleton .
Classify each animal according to whether or not it has an internal sketeleton .
Classify each animal according to whether or not it has an internal sketeleton .
Classify each animal according to whether or not it has an internal sketeleton .
Classify each animal according to whether or not it has an internal sketeleton .