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Meselson and Stahl conducted an experiment to determine the correct proposed methods of DNA replication was semi-conservative
. the three proposed models for DNA replication are semi-conservative, conservative, and dispersive.</h2>
Explanation:
In Semi-conservative replication model, the two strands of DNA uncoil from each other. It perform with the original strand and a new strand.
In Conservative replication model, DNA replication didn't open at all, but the parent strands remains undamaged by creating a new and separate  molecule that consists of two new strands.
In Dispersive replication model, DNA replication results in two DNA molecules that consists of both parental and daughter DNA. 
He demonstrated that semi-conservative DNA replication is an universal mechanism allocated by all organisms on Earth.
 
        
             
        
        
        
Answer:
I'm more then sure it is A but let my know it im wrong if i am sorry :)
Explanation:
 
        
             
        
        
        
An under water volcano is called a submarine valcano
        
                    
             
        
        
        
<u>Answer:</u> 
To help relieve heartburn, a person should take medicine that is 'Over-the-counter (OTC) antacids and acid blockers'.
<u>EXPLANATION:</u>
- Heartburn is a very common symptom of a condition called Gastroesophageal reflux disease. 
 
- This affects the lower part of the esophageal sphincter and also the muscle ring-like connection between the 'esophagus and stomach' which tends to infuse a backward flow of the stomach secretions. 
 
- Along with some dietary and life style changes, the intake of antacids and acid blockers can help in the relieve of the symptoms of occasional heartburn.
 
 
        
             
        
        
        
The answer is A. RNA polymerase will be making an mRNA using a single DNA strand as a template. So, for example if the DNA strand is AGGCAGC the mRNA strand will be UCCGUCG.
U= uracil which replaces thymine in mRNA molecules.
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i hope my answer helped!!!!!!!</span>