During gaseous exchange in the lungs, carbon dioxide moves
Correct answer: C. from the blood into the alveolar air
- A. from the alveolar air into the blood
- B. from red blood cells into haemoglobin
- C. from the blood into the alveolar air
- D. from the plasma into the lymph
Explanation
Venous blood arrives with a higher CO2 pressure than alveolar air, so the gas diffuses out to be exhaled. The opposite direction would defeat the entire purpose of ventilation.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About Human Respiratory System
The human respiratory system conducts air to the alveoli, where oxygen and carbon dioxide exchange occurs across thin respiratory surfaces. Questions cover the nasal passage, trachea, bronchi, lungs, diaphragm and intercostal muscles, ventilation mechanics and gas transport, while distinguishing breathing and gaseous exchange from cellular respiration.
Practise Respiration
446 free Respiration MCQs from Biology, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Biology questions like this
Biology is on 8 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Human Respiratory System questions
Between the air in an alveolus and the blood, oxygen must cross
Which of the following is NOT a characteristic of an efficient respiratory surface?
When blood reaches the respiring tissues, haemoglobin
The sticky brown substance in tobacco smoke that carries most of the carcinogens is
Which of the following is NOT caused by smoking?
Babies born to mothers who smoke during pregnancy often have