Calcite is the most common rock
        
                    
             
        
        
        
Four bands appear in gel electrophoresis. Gel electrophoresis is an experimental method used to separate mixtures of DNA, RNA, or proteins by molecular size.
DNA is negatively charged, so when a current is applied to the gel, the DNA migrates towards the positively charged electrode. Fragments are ordered by size because short DNA strands migrate through the gel faster than long strands. There are some basic steps for performing gel electrophoresis outlined below. 1) pour the gel, 2) prepare the sample, 3) load the gel, 4) run the gel (expose it to an electric field), 5) stain the gel. Gel electrophoresis is a technique for separating biomolecules by size. Separation of these molecules is achieved by placing them in a small pore gel and creating an electric field across the gel
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Intelligence is most likely to be the criteria for random mating in humans.
Explanation:
If random mating is taking place on the conditions that no evolution is taking place the genetic pool will be maintained through generations.
Random mating will be based on intelligence in humans because this is the trait which gets exhibited only when showcased otherwise remains hidden while other characters like personality, appearance and athleticism are phenotypically expressed character. 
Random mating is not under the influence of genotype. Intelligence is a trait which needs to be more in human as random mating takes genotype frequency in consideration.
 
        
             
        
        
        
I believe that the best answer for this question is false. The individual who was the first to describe microbes was Antonie van Leeukwenhoek. He is considered to be the Father of Microbiology and the first microbiologist. Hook was actually his contemporary. I hope this helps.
        
                    
             
        
        
        
Answer: A.They contain plants that purify water.