Breathing

All living things breathe in and breathe out ________

If the respiratory rate of 'A' is 35 breaths/min and tidal volume 185 cc/breath and of 'B' is 25 breaths/min and tidal volume 259 cc/breath then

Air is breathed through

Earthworms breathe through their

Air is breathed through

When you hold your breath, which of the following gas changes in blood would first lead to the urge to breathe