Answer:
I agree it would be A) IT is a reactant in a chemical reaction
Explanation:
a catalyst is a substance that causes a chemical reaction to happen in a different way than it would happen without that catalyst
EARTH'S PROTECTIVE SHIELD. Earth is surrounded by invisible gases that form a thin protective blanket that we call the atmosphere. It contains the oxygen that we breath as well as other important gases such as nitrogen, carbon dioxide, water vapor, and ozone.
Generally people would say that the result are published in journals, and it is true that Journals are often the first opportunity for many people to read about those results.
However, it takes a long time to publish in a journal, and people often present their results to a smaller audience at a conference before the journal is ready.