scientists can test differences of the area with pigmentation by observing which is lighter and which is darker however they use microscope to look the difference of the pigmentation over the cells.
Answer:b) The air at high altitudes are less dense, so its harder to breathe.
Explanation:
AS altitude increases, the air pressure drops. This reduces the amount of gas molecules in the air so the air becomes less dense compared to air closer to sea level.
Answer:
The force of friction is reduced between the blocks by adding the dishwashing liquid because the liquid is slippery and this makes it difficult for the two surfaces to contact each other directly. Therefore the blocks slip past each other rather than grinding against each other, producing less friction.
Explanation:
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