Which of the following organs is the main site for gas exchange in the human body?

• Trachea

• Bronchi

• Alveoli

• Larynx

What is the function of the diaphragm during inhalation?

• It contracts and moves upward

• It relaxes and moves downward

• It contracts and flattens

• It expands the lungs directly

Which structure prevents food from entering the trachea?

• Larynx

• Epiglottis

• Esophagus

• Bronchus

Which gas is transported from the lungs to the bloodstream during respiration?

• Nitrogen

• Carbon dioxide

• Oxygen

• Helium

What is the correct sequence of airflow during inhalation?

• Nose → Trachea → Larynx → Bronchi → Alveoli

• Nose → Larynx → Trachea → Bronchi → Alveoli

• Trachea → Nose → Bronchi → Alveoli

• Nose → Bronchi → Trachea → Alveoli

The tiny air sacs where gas exchange occurs are called:

• Bronchi

• Bronchioles

• Alveoli

• Capillaries

Which part of the respiratory system contains the vocal cords?

• Pharynx

• Larynx

• Trachea

• Bronchus

Which of the following best explains why alveoli are surrounded by capillaries?

• To provide nutrients to the lungs

• To remove bacteria

• To allow gas exchange between air and blood

• To increase breathing rate

Which organ helps to warm, moisten, and filter the air before it enters the lungs?

• Mouth

• Nose

• Pharynx

• Diaphragm

Which of the following statements is TRUE about exhalation?

• Diaphragm contracts

• Chest cavity expands

• Lungs fill with air

• Diaphragm relaxes and moves upward