Answer:
i think it is A but  lmk if it is wrong
Explanation:
 
        
             
        
        
        
Answer: a. oxygen
Basically what (/the) ETC and oxidative phosphorylation is, is the products of the Krebs cycle being oxidized and oxygen receiving electrons. And when the phosphorylation part of oxidative phosphorylation occurs is when ADP gains its third phosphate group becoming ATP.
Forgive me for this poor response I was trying to be quick and it resulted in this vague and disorganized mess. To properly explain the ETC and oxidative phosphorylation it would be best to start from the beginning and explain all the stages of Aerobic respiration. Then it would be easier to Segway in to this final stage which would definitely take 2-3 descriptive paragraphs to cover.
 
        
             
        
        
        
Answer:
The suns average density is greater than water's.
Density (avg) of the sun: 1.4 g/cm
Density of H20: 1.0 g/cm
Have a good day! 
 
        
             
        
        
        
Answer:
having exactly the same DNA sequences, twins start accumulating genetic variation from the earliest stages of development, researchers at Iceland-based company deCODE genetics found, meaning that one twin harbors variants that aren't present in the other.