The outer covering of an adult sea squirt is called the .
mantle
exoskeleton
shell
tunic
Why are sponges considered metazoans and all otheranimals considered eumetazoans?
| | Sponges are prokaryotes, whereas other animals areeukaryotes. |
| | Sponges lack true tissues, whereas other animals have truetissues. |
| | Sponges do not have heads like other animals. |
| | Sponges are colonial organisms, whereas other animals aremulticellular organisms. |
What do bivalves and tunicates have in common?
| | They are both close relatives of vertebrates. |
| | They are both soft-bodied lophotrochozoans. |
| | They are both filter feeders. |
| | They both have larvae with notochords. |
