Answer:
<u>Pruning</u>
Explanation:
Pruning or synaptic pruning is brain's way of clearing unnecessary signals that are no longer needed. It mostly occur in childhood and adolescence because brain want to get faster by avoiding unused impulses in Synapses. Synapse is the space between neurons through which signals are being transferred.
 
        
                    
             
        
        
        
Scales of a fish, I kind of read or heard people getting drafts of fish skin which might be the same.
        
             
        
        
        
Answer:
the answer is  c) Test subjects may get bored and want to quit early.
Explanation:
 
        
                    
             
        
        
        
Sickle-cell anemia is caused by a point mutation in the β-globin chain of hemoglobin, causing the hydrophilic amino acid glutamic acid to be replaced with the hydrophobic<span> amino acid valine at the sixth position.</span>
        
                    
             
        
        
        
<span>C. Single events or several causes working together to produce extinction in a short period is referred to as mass extinction.
Example:
</span>Destruction of forests, mountains, and bodies of water to satisfy human needs result to the imbalance of nature which also give rise to global warming.
<span>Animals and plants have lost their habitats. They lost their means to live. They lost their food sources and they suffer and die because of humans irresponsible acts.</span>