Students have been remaining for a long time in a badly ventilated room. They developed respiratory changes caused by irritation of their peripheral chemoreceptors that react primarily to:

Answer options

1. Decrease of oxygen tension in arterial blood
2. Decrease of carbon dioxide tension in arterial blood
3. Increase of hydrogen ion concentration in arterial blood
4. Decrease of hydrogen ion concentration in arterial blood
5. Increase of oxygen tension in arterial blood