Answer:
used to date rocks and other objects based on the known decay rate of radioactive isotopes.
Explanation:
Different methods of radiometric dating can be used to estimate the age of a variety of natural and even man-made materials.
Atmospheric pressure at sea level is 760 mmHg.
We have been told that at the summit the pressure is only one third the pressure at sea level.
Then the pressure at the mountain top is

mmHg
Air is made of a mixture of gases. the pressure that each gas exerts individually contributes to the total pressure of the system. The pressure that each gas exerts is the partial pressure of that gas which depends on the mole fraction of that gas or percentage composition of the individual gas.
Partial pressure of Oxygen - total pressure x percentage composition
Therefore pO₂ -

= 53.2 mmHg
Answer is 53 mmHg
Did you ever get the awnser to this question cause im stuck on it too