Select the one animal that has all of the cartilaginous fish traits listed above.
Amazon milk frogs have moist skin and live in South American rain forests. They hatch from eggs with no shells and begin their lives in water. As adults, Amazon milk frogs live in trees and eat insects. Manta rays have wide, triangle-shaped fins that help them swim long distances. They have a skeleton made of cartilage, not bone. Manta ray eggs do not have shells for protection. Instead, the eggs grow and hatch inside the mother manta ray.
Cartilaginous fish are a group of animals with similar traits. The following traits can be used to identify cartilaginous fish:
They have fins, not limbs.
They live underwater.
They have a skeleton made of cartilage.
They make eggs with no shells. 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.
Cartilaginous fish have the following traits:
They have fins, not limbs.
They live underwater.
They have a skeleton made of cartilage.
They make eggs with no shells.
Compare each animal's traits to the group's traits. Select the animal with traits similar to the group's traits.
An Amazon milk frog has the following traits:
It spends part of its life in water and part on land.
It has moist skin.
It makes eggs with no shells.
An Amazon milk frog does not have all of the traits of a cartilaginous fish. An Amazon milk frog is an amphibian.
A manta ray has the following traits:
It has fins, not limbs.
It lives underwater.
It has a skeleton made of cartilage.
It makes eggs with no shells.
A manta ray has the traits of a cartilaginous fish. A manta ray is a cartilaginous fish.