Erythropoiesis. The process through which new red blood cells are created; it begins in the bone marrow. Mentioned in: Porphyrias. the formation of red blood cells (erythrocytes) from stem cells in the bone marrow.
2 Unicelluar organisms are one-celled organisms or microorganisms. Although they are living things that are only one cell, they still need to carry out all 6 characteristics of life. For example, they must feed, digest, excrete wastes and reproduce. They are very small and surround you every day by the millions.
Examples of unicellular organisms are bacteria and archea. On the other hand, multicellular organisms are those that house a multiple number, or many, cell types. These organisms are usually larger in size, have more specialized functions, and are classified as the eukaryotes.