Cell specialization refers to the procedure, which takes place after cell differentiation where the newly produced cells are structurally converted so that they can do their activity efficiently and effectively.
One of the examples of specialized cells is red blood cells, which develops in bone marrow in many phases. From a hemocytoblast, a multipotent cell in the mesenchyme turns into an erythroblast; after two to five days of development, the erythroblast slowly gets occupied with hemoglobin, and its nucleus and mitochondria get disappear.
In the later phase, the cell is known as reticulocyte that eventually turns into a complete mature red cell. The average red cell in humans survives for 100 to 120 days.
The answer is In the last trimester of pregnancy. While the senses
of the fetus start to develop in the 8th week, the different sense mature
at different stages. Vision is the last sense to mature. After the 26th
week, after the eyelids of the fetus have
fully developed, the fetus begins to blink (even experience REM while involves rapid
eyelid movements ).
