I think it is the third statement
‘A unit is made up of two or more atoms’
Hello
The word is "pollution"
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2.B. Describe the difference between a reaction that occurs spontaneously and one that does not. Spontaneous chemical reactions release energy and use that energy to power itself; non-spontaneous chemical reactions need to absorb energy, which they can't absorb their own energy that they don't even have.
The receive very little rainfall
The compound that was formed by the reaction of the first oxygen released by Cyanobacteria and iron are the metals of the earths crust. Cyanobacteria was the first organisms that used water instead of hydrogen sulfide or other compounds as a source of electrons and hydrogen for fixing carbon dioxide. Early Cyanobacteria inhabited marine sediments where Archean banded iron formations were deposited; consisting of reddish layers rich in iron oxide.
