f.4 bio,,about cell..急急急!!

a. The haemoglobin in the red blood cell react with very concentrated saline .
to form precipitate. so no red blood cell which contains haemoglobin is
present in the solution, so it is not red.

b. In tube B, the very dilute saline cannot react with all haemoglobin in red
blood cell, so some is left in the solution, so it show light red color due to
the present of haemoglobin.

c. Some red blood cell is present under a light microscope.

d. The amoeba will damaged by saline in the sea water, so it can not work, so
they die in sea water.
OR
The amoeba has a higher water potential than the sea water, so the amoeba
will loss water by osmosis, so the cell shrink.