[填空题]
The image below is a micr wrsn1 49;kpfjograph of bh)si g* zv5ikrg9-a: rlood.
1.Identify the part of the cells labelled A and B.
arrow points to the plasma membrane
arrow points to the nucleus
2.Outline why blood is classified as a tissue.
3.State where the stem cells needed to produce red blood cells are located.it is .
4.Progenitor cells are produced by dividing stem cells. These cells will eventually differentiate even further. Blood cells have a common progenitor cell. Describe the process that happens to these progenitor cells.
