It is a physical change, as only the dimensions changed, not the chemical structure.
Answer:
25km/h
is that the full question
Explanation:
Her cells will not work well when they have low levels of oxygen.
Possibly something that interacts with the earth's magnetic field and produces the spectacular "Northern Lights", or "Aurora Borealis" if you prefer latin. Charged particles moving at relativistically high speeds, some of which may be from the sun via solar flares. I think that mu mesons are cosmic rays. First discovered by a scientist in a hot air balloon (he 'd gone up with instruments to detect them), and later used to verify the time dilation result of special relativity by MIT and the "mount washington experiment".
Answer:
A microwave
Explanation
The human retina can only detect incident light that falls in waves 400 to 720 nanometers long, so we can't see microwave or ultraviolet wavelengths. This also applies to infrared lights which has wavelengths longer than visible and shorter than microwaves, thus being invisible to the human eye.
