The cytochrome oxidase test is used primarily for the identification of GRAM NEGATIVE ORGANISM.
The oxidase test is used to identify bacteria which synthesize cytochrome C oxidase enzyme, which is an enzyme of the bacterial electron transport chain.
Answer: Sunlight
Explanation: Photosynthesis, the process by which green plants and certain other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds.
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Yeast is very similar to human cells in that we have the same cellular respiration process. The formula for cellular respiration is C6H12O6(Glucose) + O2(Oxygen) = CO2(Carbon dioxide) + H2O
Because of this we know that the yeast is going to take oxygen from the air and the glucose in the test tube and produce carbon dioxide with it, so the full answer would be “The composition of the air in the test tube would change so that there is a higher composition of CO2.” If you need to explain it more pull from my explanation :)