Bio H (and curious Bio R students) should continue on from this point. 
For others, you are done with this activity.  Sorry!

Frog video was located here. 

3.      Subsequent growth of groups of similar cells (known as   T I S S U E  layers)

    The  E C T O D E R M   (Ref. #25)  comes from the outer tissue layer of the gastrula. 

    The   M E S O D E R M   (Ref. #26) comes from the middle tissue layer of the gastrula.

    The   E N D O D E R M   (Ref. #27) comes from the inner tissue layer of the gastrula. 

      a.       The s k i n,  h a i r  and C N S (central nervous system)  (Bio Disk # 2860P) form
from  OUTside  (E C T O D E R M)  embryonic tissue layers.  Ref. #25

     Which of these three tissues or organs (prior sentence) does not seem logical, since
this region is now totally hidden within your body?   _C NS_  The last time I looked,
I didn't have the nerve to see your nervous system hanging out of your body. It
actually moved from the outside to inside of your body during early development.

b.      The middle embryo layers (M E S O D E R M ) (Ref. #26) become the
c i r c u l a t o r y,  l o c o m o t i o n, e x c r e t o r y,  and  
r e p r o d u c t i v e    systems  (g o n a d s)

c.       The d i g e s t i v e  &  r e s p i r a t o r y  systems form from INside
(E N D O D E R M)  (Ref. #27)  embryo tissue layers

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