Which of the following breathing process in human is passiv?

Oxygenated blood from lungs is carried to the heart by –

Which is correct ?

Body tissues obtain oxygen from haemoglobin because of its dissociation in tissues caused by –

When the carbon dioxide concentration in blood increases,the rate of breathing will –

During inspiration –

A normal man at rest inspires and expires about 500 millilitres of air, this amount is known as –

Every 100 ml of oxygenated blood delivers following amount of O₂ to the tissues under normal physiological contition

If O₂ concentration in tissues were almost as high as at the respiratory surface

The blood leaving the lungs has all its haemoglobin oxygenated and gives up oxygen to the tissues, because