can some one please help with this hw questions?
To get the samples of blood, a doctor first wiped the skin of each volunteer’s thumb with cotton wool soaked in alcohol (ethanol). Then the doctor pricked the thumb with a sterile needle and smeared the blood on to a microscopic slide. the smear was stained with a special dye.
a) why was the skin wiped with cotton wool and alcohol?
b)why was the needle sterile?
c)when you look at a red blood cell under the microscope the central part looks paler. why is this?
d) a drop of blood was placed on a slide and mixed with distilled water. explain what would happen.
a) Alcohol kills germs and prevents the spread of bacteria. They use ethanol often in hospitals, visitors have to use it on entering and exiting the wards.
b) The needle is made sterile again to prevent the spread of germs and so that chances of infection are reduced.
c) The central part of a red blood cell is concave, and therefore may look different under the microscope, and also the cell carries haemoglobin which carries the oxygen, I think it might be white as well as red?
d) The blood cells would swell due to osmosis.
You may want to check up on these because im a bit rusty on blood cells 
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