Answer:
complementary base-pairing rules 
Explanation:
DNA is the genetic material of living cells. It is a long chain of double-stranded molecules, in which each strand is complementary to one another i.e. Adenine base is paired with Thymine base while Guanine base pairs with Cytosine base following the complementary base pairing rule as proposed by Chargaff. This pairing is responsible for the double helical structure of the DNA. 
The complementary base pairs that a DNA molecule contains make it able to produce identical copies of itself during replication or duplication. Before replication of DNA can occur, the double strands need to unwind to form two separate strands, which serves as a template for the synthesis of new complementary strands. 
In this manner, each new strand contains one template strand and one complementary strand, which forms two new double helix that is identical to the original strand. This two identical copies of DNA gets separated into two daughter cells, which is the essence of the DNA replication.
 
        
             
        
        
        
Answer:
D. All of the above
Explanation:
Enzymes are proteins, act as biological catalysts, and are sensitive to factors like pH and temperature.
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Answer: Global warming is happening because the greenhouse gases are becoming more thicker which makes more of the suns radiation (heat) stay in the earth; as a result, this is increasing the earth's temperature.
 The subject is geography :)
Explanation:
 
        
                    
             
        
        
        
Answer:
Darwinism is a theory of biological evolution developed by the English naturalist Charles Darwin (1809–1882) and others, stating that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce.
Explanation:
 
        
             
        
        
        
Answer:
lungs i think im almost positive