A. Size, because it would determine if the molecule can fit though the pores.
        
                    
             
        
        
        
Because science involves a lot of replication to confirm results. That means without the systems, it would take a long time to get the results right.
        
                    
             
        
        
        
 
"In the early days of germ theory, contagious diseases
were thought to be caused by fungi or bacteria. In the 1890's, Dmitri
Ivanovski filtered extracts from diseased tobacco plants and discovered
that the disease could be transmitted to new plants through the
filtrate. He concluded that the disease was caused by particles smaller
than bacteria; the tobacco mosaic virus", is partially correct. Dmitri
Ivanovski discovered that filtered extracts from diseased tobacco plants
could be transmitted to new plants through the filtrate. However, it
was Dutch microbiologist Martinus Beijerinck who, while replicating
Ivanovsky's experiments, proved that the filtrate contained a new
infectious agent. Beijerinck named this agent a virus.  
        
             
        
        
        
Answer:
there like brown grayish color
 
        
                    
             
        
        
        
Answer:
one that recognizes a 2 base pair sequence would cut DDNA every 16 bases. A 3 base pair recognition site would be found every 64 bases.