Answer:
Please put this question in English and I would then love to help you. Thanks.
B . , because I remember this
Plasmid. A plasmid is a small circular DNA presents in bacterial cells. It is used as a cloning vector for DNA. The cloned DNA and the plasmid are treated with a restrriction enzyme. The enzyme will make cleaveges in the same portions of the two DNA. The plasmid is then allowed to be replicated inside the bacterial cell.
Nicotine, once in the brain, will work specifically on nicotinic receptors in the brain. However, there is a common "addiction" pathway in the brain that pretty much all addictive substances go through.