Experts, for this question, option b or d is correct In many places I find option b and in - Biology - Breathing and Exchange of Gases

Question

Experts, for this question, option b or d is correct? In many
places I find option b and in many other sites i find option d
Please explain

Sidrah Maryam · Accepted Answer

Dear student,
option b is correct
It is so because residual air has no effect on efficiency of
respiration
Thanks

Experts, for this question, option b or d is correct? In many places I find option b and in many other sites i find option d. Please explain.