1. GALACTIC BULGE
In astromy,  a galactic bulge is a tightly packed group of stars within a larger star formation. The term almost exclusively refers to the central group of stars found in most spiral galaxies.

Example: The center of a milky way galaxy is called galactic bulge.

2. CLEAVAGE
Cleavage, in mineralogy and materials science, is the tendency of crystalline materials to split along definite crystallographic structural planes.

Example: Mica is a cleavage, which cleaves in a single direction along the basal pinacoid, making the layers seem like pages in a book. 

3. SONIC HEDGEHOG
This is a protein that functions as a vital morphogenic signaling molecule and plays an important role in the formation of many different structures in developing embryos, in cell growth, cell specialization and the normal shaping (patterning) of the body. This protein is important for development of the brain and spinal cord (central nervous system), eyes, limbs, and many other parts of the body.

Example: Sonic hedgehog contributes to cell growth, cell specification and formation, structuring and organization of the body plan.

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