Well living is having life while biotic is pertaining, or produced by life or living organisms. :)
        
             
        
        
        
Most color pigmentation goes towards hair and not much is left for skin.
        
                    
             
        
        
        
Answer:
Protein
Explanation:
A protein is a naturally occurring, extremely complex substance that consists of amino acid residues joined by peptide bonds. Proteins are present in all living organisms and include many essential biological compounds such as enzymes, hormones, and antibodies.
 
        
             
        
        
        
Answer:
The correct model is D.
Note: The first attachment below shows the different models. The second attachment shows the correct structural model of the water molecule.
Explanation:
A water molecule is composed of one atom of oxygen and two atoms of hydrogen.
A water molecule is polar, i.e. it contains positively and negatively opposite ends. The polar nature of the water molecule is due to strong electronegativity of oxygen which results in an uneven sharing of the bonding electrons between oxygen and hydrogen. The oxygen atom attracts the shared electrons more to itself, thereby, it acquires a partial negative charge, while the hydrogen atoms acquire a partial positive charge.
The bond angle between the oxygen and hydrogen atoms is approximately 105°. Therefore, from the first attachment below, the correct model for the water molecule is D.