Physical Change because a new substance was not created and if it was a chemical change, a new substance would have to be created.
Light does not travel at a constant speed in a vacuum, compared to in air, because the light is being absorbed by atoms and molecules in the air. But light does travel at a constant speed in a vacuum.
So I agree with A
All that talk about moving forward is irrelevant (I think)
We have that the correct wedge and dash conformation for the following Newman projection is
IV
From the Diagrams above
Two CH_3 groups points on opposite sides in plane
Two Br are on same side of plane
Two H also on same side of the plane so the plausible structure is IV
Therefore
The Correct option is IV
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They are examples of physical<span> contaminants .</span>
