The ___________ is a strong wall of muscle that contracts to create a suction in the chest to draw in air and expand the lungs. When the muscle relaxes, the chest cavity decreases and the air is pushed out.

Answer 1

The diaphragm

Answer 2

Which of the following statements best describes how oxygen enters the lungs?
(1 point)
Responses

Oxygen enters the lungs through the trachea, which branches into two tubes called the bronchi, which lead to the lungs.
Oxygen enters the lungs through the trachea, which branches into two tubes called the bronchi, which lead to the lungs.

Oxygen enters the lungs through the diaphragm, which branches into two tubes called the trachea.
Oxygen enters the lungs through the diaphragm, which branches into two tubes called the trachea.

Oxygen enters the lungs through bronchi, which branches into two tubes called the bronchioles.
Oxygen enters the lungs through bronchi, which branches into two tubes called the bronchioles.

Oxygen enters the lungs through the trachea, which branches into the alveoli.
Oxygen enters the lungs through the trachea, which branches into the alveoli.

Answer 3

Oxygen enters the lungs through the trachea, which branches into two tubes called the bronchi, which lead to the lungs.

Answer 4

External respiration takes place in the ____________________.
(1 point)
Responses

bronchi
bronchi

trachea
trachea

alveoli
alveoli

diaphragm
diaphragm

Answer 5

External respiration takes place in the alveoli.