Scientists thought that the reason children in early studies developed leukemia was because of the viral vectors and oncogenes they contained. These oncogenes stimulated cells to reproduce therapeutic DNA. How did this cause leukemia?

a community that experiences major changes undergoes progress

lunar landing mission. apollo 11 was the first manned mission to land on the moon. the first steps by humans on another planetary body were taken by neil armstrong and buzz aldrin on july 20, 1969. the astronauts also returned to earth the first samples from another planetary body.

explanation:

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms