Invertebrates

If you ever been to a zoo and have you ever thought how the animals different or alike. Did you know that animals that  have no backbones are called invertebrates. A simplest kind of invertebrates is a sponge. Living  sponges are usually  found on rocks or other objects on the ocean flour . The water contains food and oxygen for the cells of the sponge. If you been to the ocean you may have seen a jellyfish that washed up on the beach. People who live by the ocean know enough about jellyfish to leave them alone when they see them.