​Read the following text and then answer the questions.

An invertebrate is an animal without a backbone. Invertebrates live in every part of the world.

Most of the animals on Earth are invertebrates. Invertebrates come in all different shapes and sizes. Some can be seen only through a microscope. But the giant squid is an invertebrate, and it can grow to a length of 20 meters.

The invertebrate animals can be grouped according to their features. Many of them, such as worms, have soft bodies. Jellyfish are invertebrates that have stinging tentacles. Mollusks have soft bodies as well, but most also have a thick outside shell. Oysters and snails are mollusks. Squid and octopuses are also mollusks but they do not have shells.

Other invertebrates have a hard outside covering on their bodies called an exoskeleton. These invertebrates are called arthropods. Arthropods include insects, spiders, and crabs.

​Varieties of Life