Answer:
an element is a pure substance which can not be spilt into simpler substances by chemical means 
Explanation:
examples hydrogen, oxygen, copper 
 
        
             
        
        
        
The parts of the plasma membrane is mentioned in the diagram below: 
 
        
             
        
        
        
The stimuli plants respond to will be found in the environment. Example....plants grow towars the sun.
        
                    
             
        
        
        
When organic molecules decompose, energy is released.