Answer:
C. A low-pitched parent and a high-pitched parent have a child with a medium-pitched voice. 
Explanation:
I just took the test on edge and got it right.
 
        
             
        
        
        
The correct answer is: Layer 1, layer 2, and layer 4 in all three regions.
The index fossils are fossils that are commonly used for identifying a geological period of time, and these fossils are also very wide spread, as well as having a rapid evolutionary trends. 
By this picture, we can easily see that even though we have rock strata from different regions, the same layers contain the same fossil, and it is a fossil that also is rapidly evolving so has a minor change in each layer.
 
        
             
        
        
        
They are considered to have originated from cyanobacteria through endosymbiosis—when a eukaryotic cell engulfed a photosynthesizing cyanobacterium that became a permanent resident in the cell
        
             
        
        
        
A makes the most sense, though D could actually be an Ok reason, the other two aren't reasonable, a fire safety action? The door would be better open in a fire emergancy, it makes a quicker escape
        
             
        
        
        
Your answer is B "Pituitary"
Brainliest Please