All of the following are evidence that a chemical reaction has occurred except

a. color change

b. formation of a precipitate

c. bubbles of gas

d. all of the above are evidence of a chemical reaction

what have scientists found to be the most efficient and effective way to insert new sequences into an individual? a-scientists have created genetically altered foods that release dna during digestion. b-scientists use viruses to insert specific gene sequences. c-scientists irradiate genes so that they can be absorbed through the skin.