MCQ
Why do human beings face difficulty to breath in high elevations?
- ALower $\%$ of $O _{2}$
- BTemperature lower
- CHigh pressure
- ✓Low $\rho O _{2}$
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$I.$ Double layered
$II.$ Fluid contained in it reduces the friction on the lung surface
$III.$ Its outer layer is in contact with thoracic wall
$IV.$ Its inner layer is in contact with lungs
Select the correct combination for $A, B$ and $C$


Reason : Centrosome usually contains two cylindrical structures called centrioles
The glands which are represented as $X$, $Y$ and $Z$ are