Why are orcas considered apex predators?

Sharks shake their head when they bite because they cannot chew.

What does the gray whale eat?

Describe countershading AND how it works as camouflage AND give an example of organism that displays countershading.

Which of the following is a pelagic spawner?

Demersal fishes _____.

The skeleton of the jawless fish is bone.

Which of the following is critically endangered?

Rays and skates move water across their gills through their _____.

Select all of the jawless fishes listed below.