Maybe D but at the same time it could be A
        
             
        
        
        
I guess the stomach is held in place by a variety of Muscle cells, Epithelial cells, and connecting tissues; so the answer is: all of the above.
        
             
        
        
        
The answer I came up with is Echinoderms and Chordates.
Happy studying!
        
                    
             
        
        
        
Answer:
a nucleus of Deuterium (2H)
Explanation:
 formed from two protons with the emission of an antielectron and a neutrino. In the basic Hydrogen fusion cycle, four Hydrogen nuclei (protons) come together to make a Helium nucleus.
 
        
                    
             
        
        
        
The ecosystem is an ecological system consisting of all of its biotic and abiotic factors