Plants inherit genes that enable them to produce chlorophyll, but this pigment is not produced unless the plants are exposed to light. this is an example of how the environment can influence on gene expression.
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Light has an important role in gene expression in plants by producing a number of light-induced changes. One of the examples of the light effects is that chlorophyll and the proteins required for assembling the photosynthetic apparatus are synthesized together with the enzymes needed for carbon fixation. Gene expression influenced by light includes the regulation at the level of transcription or, alternatively regulation of translation.</span>
Well, if you look at the scientific process, the first step is to have a question to base it on.
The correct option is D. Organisms work best at their optimum temperature and pH, above and below these temperature they will not be able to function as expected. It is possible that the students above use different temperature and pH when they were carrying out their experiments, this will result in different efficiency rate by the yeasts.