Answer:
A theory.
Explanation:
A scientific theory is the product of related observations supported by evidence acquired through scientific investigation. An example of a theory includes the theory of evolution (which explains observations in the fossil record, phylogenetic patterns observed in species, and these results have been aquired through scientific investgation and analysis of things like the genome of species, and archeaological evidence)
 
        
             
        
        
        
Answer:
Because they all have a different purpose
Explanation:
The epidermis provides a waterproof barrier and creates our skin tone.
The dermis, the middke layer of skin , contains tough connective tissue, hair follicles, and sweat glands.
The  hypodermis is made of fat and connective tissue.
 
        
                    
             
        
        
        
Answer:
Schleiden, Schwann, and Virchow are the 3 major contributors to the cell theory. 
 
        
             
        
        
        
The endosymbiosis explains how eukaryotic cells may have evolved from prokaryotic cells.
        
             
        
        
        
Manure supplies plants instantly with nitrogen, phosphorus, potassium and other nutrients by warming the soil