Primitive Streak

First arises from a local thickening of the epiblast at the posterior edge of the area pellucida (Koller’s sickle)

By stage 2, the primitive streak cells form a third layer that lies between the hypoblast and epiblast cells.

 By stage 3, the primitive streak has become a definitive region of the epiblast, with cells migrating through it to become the mesoderm and endoderm.

TLS Online TPP Program

#Id: 2255

#Unit 11. Evolution and Behavior

There are three basic modes of selection on a quantitative trait.

TLS Online TPP Program

#Id: 7087

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 5643

#Unit 7. System Physiology – Animal

TLS Online TPP Program

#Id: 3191

#Unit 3. Fundamental Processes

In mtDNA, The existence of D loops exposes a general principle: An origin can be a sequence of DNA that serves to initiate DNA synthesis using om strand as a Template.

TLS Online TPP Program

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#Unit 4. Cell Communication and Cell Signaling