B.
The cynobacteria were already there without the oxygen, so that rules out A, and a lot of prokaryotes were anaerobic, so that rules out C. Finally, Photosynthesis does not require oxygen. Instead, Oxygen is a waste product of it. Therefore, it cannot be D. So, we are only left with B
Hoped this helped :D
Answer:
iron (III) oxide is a gas
When using ion-selective electrodes, to compensate for a complex or unknown matrix, the standard addition method can be used to determine the analyte concentration. Option D
<h3>What are ion-selective electrodes?</h3>
Analytical chemistry is a science that deal with the measurement and detection of the accurate amount of a substance. Analytical chemistry plays a large role in environmental management as it helps in the determination of the levels of contaminants in a sample.
An ion selective electrode is used in analytical chemistry to measure the amount of a target ion by converting its activity into a measurable electrical signal.
Hence, when using ion-selective electrodes, to compensate for a complex or unknown matrix, the standard addition method can be used to determine the analyte concentration.
Learn more about ion-selective electrodes:brainly.com/question/14987024
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Answer:
heat flow
Explanation:
heat flow moves to a higher temperature to a lower temperature