cellular differentiation!

cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. 
 This is the process which allows a single celled zygote to develop into a multicellular adult organism which can contain hundreds of different types of cells. 

 1. The Morula Stage

2. The Blastula Stage

3. The Gastrula Stage

4. The Neurula Stage

The germ layers and the systems formed from them:

Endoderm- The endoderm forms the epithelial lining of the whole of the digestive tube except part of the mouth and pharynx and the terminal part of the rectum.

Mesoderm- The mesoderm forms the skeletal muscle, the skeleton, the dermis of skin, connective tissue, the urogenital system, the heart, blood, and the spleen.

Ectoderm- The ectoderm forms the central nervous system, the lens of the eye, cranial and sensory, the ganglia and nerves, pigment cells, head connective tissues, the epidermis, hair, and mammary glands. 

bonus question answer :

blastocyst :D