What is the job of the lungs?
Which of these is an external structure?
A claw is an example of an internal structure.
Circle one: True False
A cow's stomach breaks down tough grass. Is the stomach an internal or external structure?
A porcupine is covered in sharp quills. How do the quills help it survive?
Which sentence best links a structure to a survival function?
Sam says: 'The heart takes in air, and the lungs pump blood.' What is wrong with Sam's statement?
Someone writes: 'A bird has wings.' Is this a complete argument for how a structure helps it survive?