Question

why do lungs always have residual value of air ?

Answer 1

so that their is sufficient time for co2 to be released and O2 can be able observed

Answer 2

1. lungs have got residual volume which is fixed amount of air present in lungs which provides sufficient time for exchange of gases.
2. respiratory pigment is haemoglobin present in red blood cells.
1.so that there is sufficient time for inhalation after exhaling
2.haemoglobin-respiratory pigment and found in RBC (red blood corpulses)
The lungs always contain a residual volume of air so that during breathing cycle there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.
Hemoglobin is the respiratory pigment in humans. It is present in red blood cells.