Answer:
Microlensing.
Explanation:
This techniques is called Microlensing.
Microlensing is a method of gravitational lensing where light from a backdrop point of origin is curved to develop distorted, numerous and/or lightened images by the gravity field of a foreground lens.
This method is very effective in discovering planets that are far-far from earth.It is actually an astronomical effect that was predicted by Albert Einstein's general theory of relativity.
Answer:
The value is 
Explanation:
From the question we are told
The pipe diameter at location 1 is 
The velocity at location 1 is 
The diameter at location 2 is 
Generally the area at location 1 is

=> 
=> 
=> 
Generally the area at location 1 is

=> 
=> 
Generally from continuity equation we have that

=> 
=> 
=> 
So base on your question that as if the vapors volume were to incorrectly recorded as 125ml, the effect of the error to calculate the molar mass is the same as the error in measuring the volume of the vapor. I hope you are satisfied with my answer and feel free to ask for more
Most likely B. Will erode, if not it will grow weeds