B is the answer...
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Answer:
When light travels from one medium to another, the frequency of light does not change. However, the velocity and wavelength change.
Explanation:
Pls mark me as brainliest
1)

<Solve using the formula which is:
Mass=Density×Volume

2)
3)

(Length × Width × Height)


(Answer=7.5)
That's true.
And I'll go ya a better one:
If the object is moving or not moving, at a constant or changing speed, in a straight or curvy line, and the forces on it do not cancel out and add up to zero, the object will accelerate.