In mammals, the process of ventilation is normally controlled by the autonomic nervous system. Which among the following statements does not characterizes ventilation in humans?

Afferent neurons from the carotid bodies and aortic bodies are via the glossopharyngeal nerve.

During moderate exercise, ventilation increases in proportion to metabolic production of carbon dioxide.

Ventilatory rate is usually controlled and determined by blood levels of oxygen as determined by metabolic rate.

The tone of respiratory muscle is modulated by muscle spindles via a reflex arc.

Pregnancy tends to increase ventilation.