In that case the answer is: water, carbon dioxide, and light energy (photons). 
        
             
        
        
        
Explanation:
Some things consist of only one cell. They are called unicellular organisms. One of the simplest living things, an amoeba, is made of only one cell. Amoebas (sometimes spelled amebas or amoebae) are too small to be seen without a microscope, but they are commonly found in ponds and lakes
 
        
                    
             
        
        
        
Explanation:
If gametes were produced instead by mitosis each gamete would be diploid not haploid. During fertilization of diploid gametes, the zygote would become 4n=92. With each new generation the number of chromosomes would double.
 
        
             
        
        
        
A tissue.
Then a group of tissues that work together is an organ.
The a group of organs is an organ system.
A group of organ systems is and organism.