Oxygen for the process of cellular respiration is taken from
Skin pores
Windpipe
Blood in lungs
All of these
The oxygen is carried by RBCs in blood and enter the cell through diffusion.
What is internal Respiration?
It is diffusion of gases from lungs into the blood stream.
OR
It is diffusion of gases from lungs into the blood stream. and diffusion of gases from blood streams and lungs.