The loss of complex structure and/or function that is caused by external stress or chemicals​

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.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.