Which statement is true:
| A. |
Total thickness of diffusion membrane is much less than millimetre |
 |
| B. |
Diffusion capacity of `O_2` is higher than that of `CO_2` |
| C. |
Diffusion capacity of `CO_2` is 20-25 times less than that of `O_2` |
| D. |
All of the above |