When hydrogen ions are decreased, is the pH higher or
lower?
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and for

The overall concentration of hydrogen ions is inversely related to its pH and can be measured on the pH scale . Therefore, the more hydrogen ions present, the lower the pH; conversely, the fewer hydrogen ions, the higher the pH.

the answer is b. 0; 4

blue stars have the highest surface temp

stellar distances are usually expressed in light-years

the measure of a star's brightness is called magnitude

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