The answer is option B because the number of molecules found in tea can be done experimentally in the labs. Particularly in the chemistry labs, it will be shown.
Hydrogen gas behavior is shown in chemistry practical labs. In the lab, they will teach how the hydrogen gas will behave when it is cooled.
In the physics lab, they will teach and show the microscope. They will show things inside the microscope. They will practically show the skincells in the microscope.
But the migration of birds in thousand miles will not be shown in labs. So the answer is option B
