Diffusion of Cl- from blood plasma into RBC. To maintain ionic balance & electrochemical neutrality.

O₂ will diffuse from blood into the tissues of kidney.

The partial pressure of CO₂ (pCO₂) in the alveoli should be less than the partial pressure of venous blood (deoxygenated blood) for diffusion of CO₂ from blood into the alveoli for its removal. The partial pressure of CO in venous blood is 46 mm Hg and that of alveoli is only 40 mm Hg.

Pressure exerted by the molecules of a gas in a mixture of gases.

For shock absorption and expansion / contraction while breathing in / out.

Human: RBC; Earthworm : dissolved in plasma( location based).

Combines with carbon dioxide to form carbamino-haemoglobin.

Nasal breathing is advisable because it is healthier as the air inhaled gets filtered through the hairs present inside the nose, so cleaner air reaches to the lungs.

Mammals use negative pressure to suck air in. The diaphragm contracts and move down, the intercostal muscles contract and move up and out. This causes the lungs to expand. The pressure inside the lungs drops.

The insects have network of tubes (tracheal system). The cells of the tracheal system exchange O₂ /CO₂ directly with the air by the spiracles present in insect's body.