Answer: Called the meniscus.
 
        
             
        
        
        
Fun Fact: Rubber bands last longer when refrigerated.
 
        
                    
             
        
        
        
Two species of sea urchins live practically side-by-side in sandy bottoms. The two species appear to have the same diet: drift seaweeds and other bits of organic matter. They can live in the same environment without competing.
As it compels them to live in the same environmental surroundings so the characteristics of living nature also get developed as their current following situation that's helping them to get the same food & habitat.
 
        
             
        
        
        
Answer:
pacemaker cells.
Explanation:
Cardiac muscle tissue works to keep your heart pumping through involuntary movements. This is one feature that differentiates it from skeletal muscle tissue, which you can control. It does this through specialized cells called pacemaker cells.