Answer: A
Explanation:
it’s a hands free device that prevents water being wasted 
 
        
                    
             
        
        
        
Answer:
12.00 g C-12 = 1 mol C-12 atoms = 6.022 × 1023 atoms • The number of particles in 1 mole is called Avogadro's Number (6.0221421 x 1023).
Explanation:
 
        
             
        
        
        
The cell is fundamental unit of structure and function in living organisms .All cells arise from pre-existing cells by division . The cell theory states that the cell is the basic unit of life and that all other cells are developed from an existing cell. This theory was developed way back in the mid of 17th century.