Answer:
A is the correct answer
Explanation:
the existed about 3.8to 4.0 billion years ago
<h2>CNS </h2>
Explanation:
An example of a myelin producing cell in the CNS is oligodendrocyte
- The major function of oligodendrocytes is the formation of myelin
- Myelin acts as an insulator of axonal segments and is a prerequisite for the high velocity of nerve conduction
- Larger axons form thicker myelin
- During development, oligodendrocytes arise from precursors located in the sub-ventricular zone such as the sub-ventricular zone of the lateral ventricles for the cerebrum or the fourth ventricle for the cerebellum
- In the spinal cord, oligodendrocytes originate from the ventral regions of the neural tube and in the optic nerve they migrate into the nerve from the third ventricle
- It is the oligodendrocyte precursor cells which migrate to their destination where they then differentiate into the more mature oligodendrocytes
- The proliferation of the oligodendrocyte progenitor cells is controlled by a number of growth factors released predominantly from neurons but also from astrocytes such as platelet derived growth factor (PDGF) or fibroblast growth factor (FGF)
Gastropod
Hope this will help you
<em>Hugs ~L</em>
That would be called pseudocyesis.
Pseudocyesis is when a woman thinks she is going into labor, also called a false pregnancy. <span />
Human reproductive cloning should not now be practiced. It is dangerous and likely to fail.
