What does 'adaptation' mean in this lesson?

• A weather change that happens around an animal
• A feature or behavior that helps an animal survive
• A place where an animal finds its food each day

Which layer helps a walrus slow heat loss while swimming in cold water?

• Blubber, a layer of fat under its skin
• Air held mainly inside a thick coat of fur
• A white coat that blends into nearby snow

A polar bear's pale fur color makes heat for its body.

A seal's blubber is insulation. What does that tell you?

• It slows heat leaving the seal's body.
• It makes new body heat without using food.
• It stops all heat from ever leaving the body.

How does a polar bear's dense underfur help it keep body heat?

• It produces extra heat whenever cold air touches the coat.
• Its pale color warms the skin by matching the snow around it.
• It traps air near the skin and slows heat loss.

Why do some Arctic birds migrate south for winter?

• To make their feathers match the white winter snow
• To reach places with food and open water
• To grow the fat layer that takes the place of all their feathers

Warm blood going toward a penguin's feet passes beside cooler blood returning to its body. How does this save body heat?

• Heat passes from outgoing blood to returning blood.
• Heat passes from the cooler returning blood into warmer outgoing blood.
• The two blood flows mix together and become equally warm before the feet.

Zoe says every polar animal survives through thick white fur. Which example challenges her claim?

• Polar bears have dense fur that slows the loss of body heat.
• Many Arctic foxes have white winter fur that blends into snow.
• Seals use blubber, and some birds migrate.