Answer:
there were only anaerobic heterotrophic bacteria (the primordial atmosphere was virtually oxygen-free).
 
        
             
        
        
        
Answer:
The correct answer is A  bacteriophages inject only DNA into the bacteria.
Explanation:
Bacteriophages are a specific type of virus that infect bacteria.During the course of infection bacteriophage releases an enzyme known as lysozyme which creates a hole in the cell wall of the bacteria.
    After doing that(creating a hole) bacteriophage inject its DNA inside the bacterium.
    The injected DNA undergo gene expression by utilizing the gene expression machinery of bacteria which ultimately result in the formation of coat protein.The DNA is then packed within the coat protein to form progeny phages.The progeny phages then disrupt the cell wall and get released from the bacterium in search of a new host. 
 
        
             
        
        
        
For the answer to the question above asking <span>In aerobic respiration, what is the direct source of energy that ATP synthase uses to synthesize ATP?</span><span>I think this is Proton Gradient. It is t</span><span>he product of the electron transport chain. A higher concentration of </span>protons <span>outside the inner membrane of the mitochondria than inside the membrane is the driving force behind ATP synthesis.</span>
        
             
        
        
        
C. Glycolysis produces pyruvate, ATP, and NADH by oxidizing glucose. 
 
        
                    
             
        
        
        
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