Scientists have recently modified the bacteria that cause tooth decay by inserting a fragment of dna into the bacteria's dna that prevents it from producing lactic acid. what is the new dna called?
foreign dna
restriction dna
recombinant dna
transgenic dna

recombinant DNA is the correct answer to your problem

Recombinant DNA.

Explanation:

Recombinant DNA may be defined as the DNA molecule obtained from the genetic material of different sources of organisms. Recombinant DNA is also known as chimeric DNA.

A new DNA fragment has been introduced in the bacterial DNA that prevents the formation of lactic acid. Since, the source of DNA is obtained from the other organism, the resulting DNA is consider as recombinant DNA.

Thus, the correct answer is option (3).

rain is the best answer

i think its the first one