Answer:
c. cysteine
Explanation:
Cysteine is a non essential amino acid. It contains sulfur in form of thiol group. A disulfide bond or bridge is formed between two thiol groups. It is represented as S-S. It is formed by oxidation of two cysteine molecules. The resultant disulfide bond is called as cystine which connects two polypeptide chains. 
Cysteine is the only amino acid capable of forming disulfide bridge. It stabilizes protein's globular structure and plays an important role in protein folding and stability. Cysteine is required for protein synthesis, metabolic processes and detoxification. It is the part of beta-keratin which is the main protein in nails, hair and skin. If cysteine is mutated, formation of disulfide bond will be affected.    
 
        
             
        
        
        
Why did the narrator use the phrase “fit together like puzzle pieces” to describe how the cells of a developing human embryo form a human face
 
        
             
        
        
        
Any property that describes how a substance reacts with another substance when forming a new substance is the Property of Reactivity
.
Explanation:
The ability of substance to readily react with other substance to produce new product is called as reactivity. 
It describes about different methods used by the reactants to form new product. 
Sometimes one single reactant gives rise to two different products as in splitting of water during which the following reaction takes place:
H_2 O →2H_2 + O
On contrary, two substance combines together to give rise to one single product as:
2 Mg + O_2  →2MgO
 
        
             
        
        
        
Answer:
O4) All of the answer choices are correct.
Explanation:
Everyone that has teeth can be identified if they have a dental record. A forensic dentist can see what diet the person had, did they smoke, the age, the sex of the person and they are a source of DNA. We can examine the bite mark of the person in question and find out who they are. So teeth are very useful even when everything else on the remains is very badly damaged.
 
        
             
        
        
        
Chloroplasts is to conduct photosynthesis mitochondria is mostly the energy