Answer:
a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.
"chlorine acts as a catalyst promoting the breakdown of ozone"
a person or thing that precipitates an event.
"the governor's speech acted as a catalyst for debate"
Explanation:
hope its help
Answer:
bacteria
Explanation:
This bacteria includes Nitro cocci, nitrobacter and nitrospina
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The first single celled life form appeared on earth roughly about 3.5 billion years ago