I believe the answer is A.
Since the Earth is in the Milky Way and not outside it, we cannot see the exact shape of it. Physicists have been able to track and graph the movements of the planets accurately for thousands of years, but that does not mean we know the shape of the entire solar system.<span />
C.
The particles move perpendicular to the direction of the wave.
Answer:
Atom - the basic particle of matter
Density - calculated from measurements of mass and volume
Motion - calculated from measurements of distance and time
Energy - can change form and move matter
Matter - the scientific word for <em>stuff</em>
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Hope this helps! Please mark brainliest if correct :D
I believe the answer is "When a neutral atom looses an electron to another neutral atom, two charged atoms are created."