Because they would need to compete over resources.
        
             
        
        
        
Viruses have both rna and dna
        
             
        
        
        
Answer:
the chromosome are found in the nucleus of a body cell in pair
 
        
             
        
        
        
Enzymes (Catalysts) lower the required activation energy, allowing the reaction to happen more quickly. 
        
             
        
        
        
Answer:
Diffusion.
Explanation:
According to the information given before the example in the question and considering the fact that the bag was secured on both ends before being placed in the solution, provided that there were no holes on the surface of the bag, the iodine solution could have diffused through the bag into the starch solution hence the color change to black after 30 minutes.
I hope this answer helps.