If you were wearing an empty backpack and put a 3 pound brick in it, you would feel the difference but if the backpack already had 100 pounds of bricks, you would have to add 6 pounds of brick before you could feel the difference. This phenomenon is called

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myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.

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