Answer:
High Temperature, X-rays, Radiation, Some Chemicals
Explanation:
In general, mutations happen due to some error in the DNA duplication process, however, there are certain factors in the environment that can increase the incidence rate of these genetic errors. Excessive exposure to x-rays, substances present in smoke, ultraviolet light, excessive temperature, nitrous acid and some dyes present in food, for example, can favor the appearance of mutations. In general, we can say that mutations can be caused by high temperature, X-rays, radiation, some chemicals.
 
        
             
        
        
        
Answer:
The correct answer is -
1. right-handed
2. right-handed
3. positive
4. left-handed
5. negative
6. negative
Explanation:
In a circular bacterial chromosome, the structure of DNA is a right-handed double helix In a circular bacterial chromosome.
If DNA is twisted in the right-handed direction, it becomes overwound. Overwinding results in positive supercoiling takes place. If DNA is twisted in the left handd direction, it becomes underwound. Underwinding results in negative supercoiling.
f. One effect  negative supercoiling in bacterial chromosomes is to promote separation of the two strands of DNA in the double helix
 
        
             
        
        
        
2 related plants may produce similar substances that could be used for medicines