A wildlife biologist is investigating a sudden increase in the death rate among several bird species. She has not been able to determine what
disease or toxin is causing the deaths, but she has found that many of the
sick birds are exhibiting a shortage of dissolved oxygen and a buildup of
dissolved carbon dioxide in their cells.
Which of these body systems in the sick birds is most likely NOT
functioning properly?

1. efficient use of space

2. elimination of groundwater contamination

3. energy generation

4. lower carbon footprint

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.