- DNA codes fail to match accurately.
- The environment.
- Disclosure to chemical or radiation. 
- <span> Mistake in the cellular machinery</span>
        
                    
             
        
        
        
3 (I think, sorry if it’s wrong)
        
             
        
        
        
Sorry for a late answer... But here we go!
https://www.sciencelearn.org.nz/resources/102-methods-of-pollination
        
             
        
        
        
Answer:
<h2>5.storage of energy</h2>
Explanation:
- Proteins are important biomolecules that are a type of macromolecule.
-  This macromolecule is made up of a monomer that is called amino acid.
-  There are many functions of the protein molecules in living organisms.
-  They play an important role as bodybuilding molecules, as enzymes, as transporter molecules, and many more.
-  Most of the enzymes are made up of the protein molecules and regulate the metabolic process of the living organisms.
-  Certain proteins are present in the plasma membrane of the cells and play an important role in the transport of the substances across the cells, recognition of certain foreign particles, and some other functions. 
- They also play an important role in the immune system.
-  The main storage molecules of energy are carbohydrates and fats so storage of energy is not considered as the major function of the proteins because they do not involve as carbohydrates and fats.
 
        
             
        
        
        
Keratin is an intracellular fibrous protein that gives hair, nails, and skin their hardness, strength, and water-resistant properties. The keratinocytes in the stratum corneum are dead and regularly slough away, being replaced by cells from the deeper layers 
Hope this helped!
Good luck :p
~Emmy <3