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ANIMAL ACTIVITIES . 
Do you find the visceral cavity divided by a thin 
muscular wall (the diaphragm) ? Is there a diaphragm 
in the frog or fish ? In the bird ? How does the dia¬ 
phragm assist in breathing ? 
Can you find the lungs and heart ? Are they an¬ 
terior or posterior to the diaphragm ? 
