B. Complete each sentence with an appropriate word(s) from the box.
1. Animals that have a spine are called 2. Invertebrates that do not have a well-developed internal are called 3. Vertebrates are classified into groups.
4. is a hard outer covering of invertebrates.
5.___________is an example of vertebrates.
6.Invertebrates are_________and__________moving animals.
7.___________is an example of invertebrates.
8.Vertebrates have a closed___________system.
9.Invertebrates are simple animals and were believed also as the__________set if animals that lived on earth.
10.Animals without backbones are called___________.​