You go out your back door and see a tiny, shiny trail on the ground. What animal made that? It was most likely made by a snail or slug. Snails and slugs are mollusks
. These are animals with soft bodies. They are also invertebrates
, a group of animals that do not have a backbone.
Snails and slugs have long, moist bodies. Some snails live on land. Some live in freshwater. Some snails live in the ocean. Slugs, too, live on land and in water. A land snail that you might see in your yard has a coiled shell on its back. A snail can pull its body into its shell. Slugs are like snails without shells.
Snails and slugs move by creeping on a false "foot," or pseudopod
(SUE-duh-pod), on the bottom of their bodies. Their bodies make mucous or "slime." It comes out in front of the pseudopod. It makes a slippery, moist track for the snail to move along. When the slime track dries, it makes that shiny trail you might see at your house.Paragraphs 4 to 5:
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