The following puzzle is designed to check the student's understanding of how the human body functions.

To complete the grid, they have to select the answer they think is correct. If they are correct, they move on to another question and continue until they come to the end of the grid.

There are ten questions to answer.

If they answer incorrectly, they return to the question and then continue with the exercise.

There are opportunities to return to main pages throughout the exercise.