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Subject :NSO    Class : Class 7

To prepare a blood smear slide a student placed a drop of blood on a glass slide and added a drop of distilled water to dilute the blood. He then added stain (a coloured chemical used to see the cells) to it before placing the coverslip over it. When viewed, under the microscope he could not see the blood cells. Which of the following best explains this?

AThe blood cells had burst.
BThe blood had dried before the water was added.
CThe drop of water diluted the blood too much and cells dispersed too far away from each other.
DThe water caused the cells to shrink.

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