If a bacterium cannot use citrate agar will not change its color (stays green). On the other hand, if bacteria have the ability to use citrate, the medium will change its color from green to blue.
This happens because citrate agar contains pH indicator such as bromothymol blue which transforms from green to blue in alkaline conditions.
Answer:
Declining populations of phytoplankton, the basis of the marine food chain, will alter the seawater hues, potentially decimating fisheries. The world's oceans are warming and growing more acidic as a result of climate change, and a provocative new study suggests they'll be changing color too.
Explanation:
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A. The data did not support the hypothesis because more people preferred tap water.
The "rungs" of the DNA strand are made up of nitrogenous bases.