Animals have external structures that work together as a system to support survival, growth, behavior, and reproduction. External structures are structures on the outside of an organism.

• True

• False

The polar bear lives in cold, snowy environments. Which of the following characteristics of the polar bear is an adaptation to help keep it warm?

• Sharp teeth and claws

• Thick fur and layers of fat

• Large paws and strong legs

• White color and short tail

Some animals, such as porcupines, have sharp ________ on their skin to keep them safe.

• fur

• thorns

• spines

• teeth

Sharks have a tail fin and fins. They help the sharks to ...

• walk

• run

• swim

• fly

The following animals are plant-eater animals.

*Three answers

• 
• 
• 
• 

The following animals are animal-eater animals.

*Three answers.

• 
• 
• 
• 

Some animals, such as birds, have beaks, while other animals, like horses, have large mouths with flat teeth.
The difference in these structures is most closely related to -- 

• the sounds the animals make.
• the habitat the animals live in.
• the type of offspring they have.
• the types of food these animals eat.

Different kinds of animals eat different kinds of food. Some animals feed on plants. Some animals feed on other animals. Some animals feed on both: plants and other animals.

• true

• false

Mountain lions have powerful jaws and very sharp teeth to enable it to eat......

• grass

• other animals

• leaves

Antelope have mouths with flat teeth at the front. This allows them to

• bite and eat small animals

• bite and eat grass that grows close to the ground