<span>In real life, the presence of friction. Choice B</span>
Answer:
Karl Schwarzschild discovered black holes in 1916.
Hope this helps!!
My guess would be D.. Not for sure tho.
The phase contrast microscope uses out-of-phase and in-phase light rays that produce contrast areas allowing scientists to detect even a minute number of protein molecules and focus on the minute internal structures of a particle.
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Rusting ability because it is something you can see
