<span>Thymine is harder to make, but more stable. DNA needs to keep information safe for a long time, so it makes sense to use thymine. But RNA is made and used quickly, and small mistakes don’t matter as much, so the easier to make uracil does the job.</span>
        
             
        
        
        
Answer: is seen below
Explanation: 
Termination will not take place if the strings of A nucleotides following an inverted repeat of rho- independent termination ( which forms an hairpin structure)were deleted. Although, RNA polymerase may pause briefly at the hairpin, the presence of A- U base pairs is needed to destabilize the DNA - RNA interaction and to end transcription. If the string A nucleotides is not present, then transcription of RNA polymerase will continue.
 
        
             
        
        
        
B) False, Visceral Fat is more dangerous than Subcutaneous Fat that lies just under the skin around the belly, thighs and rear.
        
             
        
        
        
Answer:
D. antigen only come from microbes
Explanation:
Antigens are substances which elicits a response by the antibodies. Antigens Antigens include proteins, nucleic acids, lipoproteins, glycoproteins, and certain large polysaccharides. 
They parts of antigen molecules that initiate immune responses are called epitopes or antigenic determinants. 
 
        
                    
             
        
        
        
Answer: B . Mesoderm 
Explanation:
The intermediate mesoderm connects the paraxial mesoderm with the lateral plate, eventually it differentiates into urogenital structures consisting of the kidneys, gonads, their associated ducts, and the adrenal glands.