Identify the structure (layer) at the tip of the arrow.  

Identify the PHYLUM represented here.  (Hint: This is a cross-section of a planarian at 400x.)  

PHYLUM represented here?  

Identify the CLASS of the organism shown here.  

Identify the PHYLUM of the organism shown here.  

Identify the PHYLUM represented here.  

Which type of holoblastic cleavage is shown here?  

Which statement best describes how a gold crown will appear on an image? 

Identify the structures at the tip of the arrows.  (Hint: this is a Hydra tentacle at 400x.)  

mA controls the ___________ of the cathode which determines the _______ of x-rays emitted.