Explain the effect of expressing only S1 on the cells in culture 1. Describe the effect of expressing combinations of protein S and protein R on the survival of the cells in culture 2 AND culture 3.

it's     c       this is a cell (b) with a nucleus (c) containing dna (a). the dna is organized into chromosomes (d). a section of the chromosome that codes for a trait is called a gene (e).

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

the answer is c. have a great day; )