Answer:
UUAACG
Explanation:
The complementary strand of the DNA strand AATTGC would be UUAACG.
The complementary nucleotide for Guanine [G] will be Cytosine [C] and applies to both DNA and RNA. But the complementary nucleotide for Adenine [A] will be Thymine [T] in DNA and Uracil [U] in RNA. 
A codon is a triplet of nucleotides, so it could be any three nucleotides in the strand. Example: AAT, ATT, TTG or TGC.
 
        
             
        
        
        
Weathering describes the breaking down or dissolving of rocks and minerals on the surface of the Earth.
        
             
        
        
        
D. Cyanobacteria one of the first beings
        
             
        
        
        
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