When bacteria use citrate, the medium becomes alkaline, and the bromthymol blue indicator will be when bacteria use citrate, the medium becomes alkaline, and the bromthymol blue indicator will be green yellow clear black blue

Blue

Explanation:

The test is called Simmons citrate agar tests (based on how organisms can utilize citrate). It can be used in differentiating the Enterobacteriaceae.

In this case, the organism is citrate positive if the medium turns blue

the median of the data is 4.5.

the answer is b.) hydrogen bonds between bases.