During exercise, your muscles work harder and need more oxygen. Which of the following explains why your breathing rate increases during this time?

• Because your alveoli collapse and need more air to open again

• Because your alveoli collapse and need more air to open again

• Because your lungs need to rest and release energy without oxygen

A student inhales deeply before running a race. Which sequence of events best describes what happens in his body during inhalation?

• The diaphragm relaxes upward, the ribs move down, and the chest cavity becomes smaller, pulling air into the lungs
  
  

• The diaphragm contracts downward, the ribs move up and out, and the chest cavity becomes larger, drawing air in

• The trachea contracts while the alveoli expand to store oxygen for later

Imagine that a person has a disease that damages many of their alveoli. What is the most likely effect on their ability to live a normal life?

• They will absorb oxygen more efficiently and have more energy

• They will struggle with gas exchange, making it harder to get oxygen into the blood and remove carbon dioxide

• Their trachea will automatically make more blood cells to help carry oxygen

Why is it important that the walls of the alveoli and capillaries are only one cell thick?

• To make them stronger so they cannot collapse under pressure

• To allow oxygen and carbon dioxide to diffuse quickly between air and blood without using energy
  
  

• To keep oxygen stored inside the alveoli until the body needs it

If the diaphragm were to stop contracting and relaxing, which of the following would immediately happen?

• Breathing movements would stop, and the lungs would no longer take in or push out air

• The alveoli would continue to exchange gases as normal

• Oxygen would still enter the blood through plasma without movement of air

When resting, a person breathes about 0.5 liters of air with each breath. What is this amount of air called?

• Vital capacity

• Tidal volume

• Residual volume

A mountaineer climbs to a very high altitude where the air has less oxygen. What problem might he experience in his body?

• The blood will carry too much carbon dioxide and not enough oxygen, causing shortness of breath and dizziness
  
  

• The alveoli will expand and store extra oxygen for emergencies

• His diaphragm will stop moving since no oxygen is available

The main job of respiration inside cells is to:

• Store oxygen for when the body is tired
  
  

• Release energy from glucose using oxygen so that cells can perform their activities

• Remove waste materials directly from the blood

Which part of the respiratory system is supported by rings of cartilage to ensure it always stays open for air to pass through?

• Bronchiole

• Trachea

• Diaphragm

Which gas moves from the blood into the alveoli so that it can be exhaled?

• Nitrogen

• Carbon dioxide

• Oxygen