in the blood
well a blood cell is only one cell and all of them usually live in the blood stream unless you get cut or get a blood blister or you get internal injuries.
Amoeba
Organism.
it would be a organism.
no
they need the heart to pump them
120 days
Heterotrophs, they don't produce their own food.
you can't the closest you can get is your own blood
Several cell types in our own immune systems have such nuclei
A sickled red blood cell will live for 10 to 20 days before it is destroyed. A normal red blood cell would have lived for about 120 days. This is the cause of the anaemia in sickle cell anaemia patients, who typically live for about 45 years.