Select the one animal that has all of the crustacean traits listed above.
Rock lobsters can live more than 600 feet underwater! They have an exoskeleton and two pairs of antennae. Trichina worms have soft, thin bodies. They have a cylindrical shape and do not have limbs. Trichina worms are not made up of segments. They can infect and feed off of humans, pigs, and other mammals.
Crustaceans are a group of animals with similar traits. The following traits can be used to identify crustaceans:
They have two pairs of antennae.
They have an exoskeleton. Observe the animals and read the descriptions.
Scientists sort animals with similar traits into groups. This is called classification. Classification helps scientists learn about how animals live.
How do scientists classify animals? First, they make observations about an animal. Scientists observe the animal's traits, including its body parts and behavior. Then, scientists compare the animal's traits to other animals' traits. Scientists classify animals with similar traits into a group.
To decide if an animal is part of a group, look at the traits of the group.
Crustaceans have the following traits:
They have two pairs of antennae.
They have an exoskeleton.
Compare each animal's traits to the group's traits. Select the animal with traits similar to the group's traits.
A rock lobster has the following traits:
It has two pairs of antennae.
It has an exoskeleton.
A rock lobster has the traits of a crustacean. A rock lobster is a crustacean.
A trichina worm has the following traits:
A trichina worm does not have all of the traits of a crustacean. A trichina worm is a roundworm.